Real bus speeds of Via 266 chipset and DDR

[Jon D]

I'm posting to get some advice about REAL bus speeds.

I want to know how much my chipset and processor would benefit from
different memory. The trouble is that I have become confused by
"effective bus speed" and "actual bus speed" and "nominal bus speed"
and so on.

As you may be tired of hearing (!) I am running a Duron Applebred
1800 in a Via 266 mobo made by Syntax with 768 KB of 133 SD-RAM. The
BIOS is by Phoenix. The CPU temp under load is ok at 44 degrees C.

The manual for the mobo is available at http://tinyurl.com/9rc5d
(OR http://64.168.125.230/support/SyntaxDownloads/download_manuals/
manual_sv266a.pdf)

My Syntax mobo can run either SD-RAM or DDR. I am thinking that I
could upgrade the 768MB of 133 SD-RAM to DDR in order to get an
increase in performnce.

Then later on this year, I can build a faster PC using all new parts
except for the DDR which I could take from the existing Snytax mobo.
(I would put the slower SD-RAM back into the Syntax mobo to create a
basic PC.) I do not want to spend more money than I have to as I am
on a budget.

QUESTION ONE. What speed DIMM memory would work well with my
Via266/Duron1800 and yet still be good to use with a faster processor
later this year which will probably be a mid-power socket 939 (and
some mobo chipset which I haven't decided on yet)? Is PC2700 too
slow?

QUESTION TWO. How fast does the bus on my mobo/cpu actually run
these devices at:

(a) the "133/266 MHz FSB" on the cpu
(b) the bus on 133 MHz SD-RAM
(c) suitable DDR in Q.1 (PC2700 ??)
(d) the PCI bus.

Thank you guys.

 

[Alex Fraser]

I'm posting to get some advice about REAL bus speeds.

I want to know how much my chipset and processor would benefit from
different memory. The trouble is that I have become confused by
"effective bus speed" and "actual bus speed" and "nominal bus speed"
and so on.

I don't know what you mean by "nominal" bus speed, but "actual" and
"effective" are quite straightforward. The "actual" bus speed is simply the
frequency of the bus clock signal, and the "effective" bus speed is that
frequency multiplied by the (peak) number of data transfers per clock cycle.
The logic here is that since a traditional bus can make only one transfer
per clock cycle, a bus that can make two transfers per clock cycle (that is,
a Double Data Rate or DDR bus) has the same peak transfer rate as a
traditional bus operating at twice the frequency.

As you may be tired of hearing (!) I am running a Duron Applebred
1800 in a Via 266 mobo made by Syntax with 768 KB of 133 SD-RAM. The
BIOS is by Phoenix. The CPU temp under load is ok at 44 degrees C. [snip]
My Syntax mobo can run either SD-RAM or DDR. I am thinking that I
could upgrade the 768MB of 133 SD-RAM to DDR in order to get an
increase in performnce.

I think the increase will be modest (perhaps up to 10% - not normally
noticeable), but I don't have any figures to hand.

Then later on this year, I can build a faster PC using all new parts
except for the DDR which I could take from the existing Snytax mobo.
(I would put the slower SD-RAM back into the Syntax mobo to create a
basic PC.) I do not want to spend more money than I have to as I am
on a budget.

QUESTION ONE. What speed DIMM memory would work well with my
Via266/Duron1800 and yet still be good to use with a faster processor
later this year which will probably be a mid-power socket 939 (and
some mobo chipset which I haven't decided on yet)? Is PC2700 too
slow?

PC2700 may be usable but if so will limit performance on faster processors;
it would be better to go for PC3200.

QUESTION TWO. How fast does the bus on my mobo/cpu actually run
these devices at:

(a) the "133/266 MHz FSB" on the cpu
(b) the bus on 133 MHz SD-RAM
(c) suitable DDR in Q.1 (PC2700 ??)
(d) the PCI bus.

I'm not sure what you are asking here. The FSB, memory bus and PCI bus are
all separate. Usually the clock signals for each are derived (via
dividers/multipliers) from a common source, so it's not strictly true to say
they are independent.

Alex

 

[GT]

QUESTION ONE. What speed DIMM memory would work well with my

PC2700 may be usable but if so will limit performance on faster
processors;
it would be better to go for PC3200.

Simply for explanation purposes I would add that PC2700 is another name for
DDR333 and PC3200 is another name for DDR400.
DDR stands for Double Data Rate, so does 2 transfers per clock tick so...
DDR333 is guaranteed to be stable on bus frequencies up to 166.666MHz and
DDR400 can run on buses up to 200MHz. DDR400 memory (200MHz) can be used at
slower frequencies - the rating is its maximum stable speed.

 

[Cuzman]

Jon D wrote:

" QUESTION ONE. What speed DIMM memory would work well with my
Via266/Duron1800 and yet still be good to use with a faster processor
later this year which will probably be a mid-power socket 939 (and some
mobo chipset which I haven't decided on yet)? Is PC2700 too slow? "

You need PC3200 for any socket 939 CPU.


" QUESTION TWO. How fast does the bus on my mobo/cpu actually run
these devices at:
(a) the "133/266 MHz FSB" on the cpu
(b) the bus on 133 MHz SD-RAM
(c) suitable DDR in Q.1 (PC2700 ??)
(d) the PCI bus. "

These two articles explain all the relevant frequencies:
http://www.tweakfactor.com/articles/tweaks/neoocguide/3.html
http://arstechnica.com/paedia/r/ram_guide/ram_guide.part3-1.html

The FSB of your CPU, chipset and SDRAM is 133.33r MHz. PC2100 DDR SDRAM
has the same bus rate as PC133 SDRAM, but is called DDR266 because it
can transfer data on both the rising and falling edge of the clock
cycle. It doesn't actually double the effective bus rate of 133.33r
MHz, and the claims of it operating at 266.66r MHz are arguably just
marketing speak.

The PCI and AGP bus work on dividers of the motherboard chipset bus.
When operating a chipset bus of 133.33r MHz, your PCI bus will work on a
divider of 1/4, equalling 33.33r MHz. Your chipset bus can also operate
at 100 MHz with slower processors, from which the PCI bus will operate
on a divider of 1/3, also equalling 33.33r MHz. Your motherboard's AGP
bus can operate at AGP4x, four times the speed of the PCI bus, thus
equalling the chipset bus of 133.33r MHz.

 

[Mike Walsh]

QUESTION ONE. What speed DIMM memory would work well with my
Via266/Duron1800 and yet still be good to use with a faster processor
later this year which will probably be a mid-power socket 939 (and
some mobo chipset which I haven't decided on yet)? Is PC2700 too
slow?

PC2100 memory will run at 266 Mhz, but if you plan on using it in a newer system you should get at least pc2700, preferably faster.

QUESTION TWO. How fast does the bus on my mobo/cpu actually run
these devices at:

(a) the "133/266 MHz FSB" on the cpu
(b) the bus on 133 MHz SD-RAM
(c) suitable DDR in Q.1 (PC2700 ??)
(d) the PCI bus.

The FSB and memory bus run at 133 Mhz. With DDR the effective speed is double because there are two data transfers per clock cycle.
PC2700 memory will run at up to 333 Mhz. It will also work with your slower bus.
A standard PCI bus runs at 33 Mhz.

 

[kony]

I'm posting to get some advice about REAL bus speeds.

I want to know how much my chipset and processor would benefit from
different memory.

Almost none except in less common apps that have very high
memory bandwidth needs. In such cases it might be upwards
of 20% or so but usually under 5%.

The trouble is that I have become confused by
"effective bus speed" and "actual bus speed" and "nominal bus speed"
and so on.

Then just ignore ALL of those terms, as none are technically
based and all just nonsense.

For any bus you have 3 parameters:

Clock generator derived frequency.
Bus Multiplier (multiplies the clock)
Data rate

So for an example, given a Duron 1.8GHz you'd have a FSB
with 133MHz clock generator, 2x bus multiplier (hence the
term "DDR", Double Data Rate), and a data rate of (in this
case) 2 X 133 = DDR266. It should not be called 266MHz
because the whole purpose of the "DDR" term is to
distinguish between clock generator rate and data rate.

As you may be tired of hearing (!) I am running a Duron Applebred
1800 in a Via 266 mobo made by Syntax with 768 KB of 133 SD-RAM. The
BIOS is by Phoenix. The CPU temp under load is ok at 44 degrees C.

The manual for the mobo is available at http://tinyurl.com/9rc5d
(OR http://64.168.125.230/support/SyntaxDownloads/download_manuals/
manual_sv266a.pdf)

My Syntax mobo can run either SD-RAM or DDR. I am thinking that I
could upgrade the 768MB of 133 SD-RAM to DDR in order to get an
increase in performnce.

Not worthwhile.
Youi'd get more gain by buying an nForce2 motherboard and
slightly overclocking (or even NOT overclocking), but then
you still need the DDR memory. KT266 chipset is simply
slower per the same data rate, clock speeds, etc, than
nForce2. This is ignoring the difference the memory makes
BUT when considering the benefit of the memory one must also
look at the rest of the bottlenecks, particularly when the
memory isn't such a large difference.

Howver, the biggest performance boost from a singular
purchase would be the CPU. Again your board is a limitation
since it only has DDR266 FSB support.

Then later on this year, I can build a faster PC using all new parts
except for the DDR which I could take from the existing Snytax mobo.
(I would put the slower SD-RAM back into the Syntax mobo to create a
basic PC.) I do not want to spend more money than I have to as I am
on a budget.

Frankly, there's no point in upgrading that system at all
then. You'd be better off waiting till you had the new
motherboard/etc so you can be sure the memory works properly
with it. I don't mean to be offensive but rather factual
when I note that- The parts are low-end stuff, as always
it's expected that it'll be more problematic and expensive
to upgrade them.

QUESTION ONE. What speed DIMM memory would work well with my
Via266/Duron1800 and yet still be good to use with a faster processor
later this year which will probably be a mid-power socket 939 (and
some mobo chipset which I haven't decided on yet)? Is PC2700 too
slow?

Yes, PC3200 CAS2.5 at a minimum.

QUESTION TWO. How fast does the bus on my mobo/cpu actually run
these devices at:

(a) the "133/266 MHz FSB" on the cpu

133MHz clock, DDR266

(b) the bus on 133 MHz SD-RAM

133MHz clock, Single Data Rate 133 ( 1 X, not 2 X)

(c) suitable DDR in Q.1 (PC2700 ??)

133 clock, Double Data Rate

The thing is, often memory isn't a major bottleneck, not as
much as CPU, hard drive, video card, all depending on the
application.

(d) the PCI bus.

33MHz. That is standard and has little to do with what
board you choose unless you try to overclock.

Thank you guys.

Frankly you should just put the money aside and upgrade
everything at once, a little sooner if you're really itching
for more performance. For many uses you might not even be
able to perceive a difference with the DDR instead of SDR
memory. System might feel a tiny bit snappier but it should
easily be fast enough at typical tasks already, with the
more demanding tasks benefitting more from a faster CPU (and
one with more L2 cache).

 

[chris]

Simply for explanation purposes I would add that PC2700 is another name
for

DDR333 and PC3200 is another name for DDR400.
DDR stands for Double Data Rate, so does 2 transfers per clock tick so...
DDR333 is guaranteed to be stable on bus frequencies up to 166.666MHz and
DDR400 can run on buses up to 200MHz. DDR400 memory (200MHz) can be used at
slower frequencies - the rating is its maximum stable speed.

You might also want to mention that if you use DDR400 with rating of CAS3,
the memory will run at lower CAS when using it at DDR333 or lower. For
instance, I have DDR400 CAS3 and is running at DDR333 CAS2.5. I'm not sure
that this is true for all brands of memory so, the BIOS should be set to
speed detect...to make sure you don't experience any problems.

 

[Wes Newell]

I'm posting to get some advice about REAL bus speeds.

See the Real Front Side Bus in link in sig line.

I want to know how much my chipset and processor would benefit from
different memory. The trouble is that I have become confused by
"effective bus speed" and "actual bus speed" and "nominal bus speed"
and so on.

Most normal people are.

As you may be tired of hearing (!) I am running a Duron Applebred
1800 in a Via 266 mobo made by Syntax with 768 KB of 133 SD-RAM. The
BIOS is by Phoenix. The CPU temp under load is ok at 44 degrees C.

The manual for the mobo is available at http://tinyurl.com/9rc5d
(OR http://64.168.125.230/support/SyntaxDownloads/download_manuals/
manual_sv266a.pdf)

My Syntax mobo can run either SD-RAM or DDR. I am thinking that I
could upgrade the 768MB of 133 SD-RAM to DDR in order to get an
increase in performnce.

Then later on this year, I can build a faster PC using all new parts
except for the DDR which I could take from the existing Snytax mobo.
(I would put the slower SD-RAM back into the Syntax mobo to create a
basic PC.) I do not want to spend more money than I have to as I am
on a budget.

QUESTION ONE. What speed DIMM memory would work well with my
Via266/Duron1800 and yet still be good to use with a faster processor
later this year which will probably be a mid-power socket 939 (and
some mobo chipset which I haven't decided on yet)? Is PC2700 too
slow?

If buying today, you should buy the fastest reasonably priced ram. I'd say
that's PC3200 which is rated for a 200MHz bus (DDR400). However, you can
use ram as slow as PC2100 (133MHz DDR266) in both your current board and
most/some A64 boards. Buying the ram today won't help your current system
much at all. Your delima is what will ram prices be later on when you
actually need the DDR ram. Ram is cheap now, but will it be cheaper later????

QUESTION TWO. How fast does the bus on my mobo/cpu actually run
these devices at:

(a) the "133/266 MHz FSB" on the cpu

133MHz clock. DDR266.

(b) the bus on 133 MHz SD-RAM

133MHz clock

(c) suitable DDR in Q.1 (PC2700 ??)

133MHz clock DDR266, but don't think that will improve performance by a
big margin. It won't. Approximately 90% of CPU data request are serviced
by the CPU cache and the speed of the external ram has very little to do
with it. At most I would guess you'd get a 5% overall performance increase
over standard sdram. You also need to remember that the ram controller is
in the chipset and all the ram data must share the FSB path to the CPU,
which is DDR even with SDR ram.

(d) the PCI bus.

It should be 33MHz on any board, but it will go higher if you overclock
the FSB and your MB doesn't have a PCI lock. And yours doesn't.

 

[Wes Newell]

Jon D wrote:

" QUESTION ONE. What speed DIMM memory would work well with my
Via266/Duron1800 and yet still be good to use with a faster processor
later this year which will probably be a mid-power socket 939 (and some
mobo chipset which I haven't decided on yet)? Is PC2700 too slow? "

You need PC3200 for any socket 939 CPU.

While PC3200 or faster would be preferred, it's certainly not a
requirement. The system will run fine on PC2700. I'm not sure what the
bottom limit is but PC2100 should also work, maybe. It will in my 754
system. From the AMD product brief...

An integrated memory controller with peak memory bandwidth of up to 6.4
GB/sec, supporting PC3200, PC2700, PC2100, or PC1600 DDR SDRAM

 

[Wes Newell]

PC2100 memory will run at 266 Mhz, but if you plan on using it in a
newer system you should get at least pc2700, preferably faster.

Nope. It's actual bus clock is 133MHz (DDR266), but not 266MHz.

 

[Sleepy]

I'm posting to get some advice about REAL bus speeds.

I want to know how much my chipset and processor would benefit from
different memory. The trouble is that I have become confused by
"effective bus speed" and "actual bus speed" and "nominal bus speed"
and so on.

I have the same board and the bus speed is 133mhz. Some sockets on the
board run on a locked ratio of that bus speed - for example the PCI slots
run at 33mhz or 1/4 and memory runs at 133mhz like your SDRAM does.
Some components on that board can run at 266mhz such as the CPU
which runs internally at double the bus speed and DDR if you install it
will run at double the bus speed.

If you put in PC3200/DDR400 it will only run at the stock speed of 133mhz
(x2 is 266mhz which is the speed of PC2100/DDR266) but you could
overclock the FSB a little if you put in that RAM - you do it in the Bios
and if you put it up to say 140mhz your CPU would perform like a 1900
or 2000. Every component connected to that board would run a little faster
and of course a little hotter so make sure your case has decent cooling if
you
do that.

Your overclocking potential is limited on that board because you can only
raise the CPU core
voltage by up to .75v - a real overclockers board would allow about 3x that
adjustment.

I went from SDRAM to DDR on this board and it made a noticeable differance -
I never benchmarked
it but most ppl say the differance is 10% - it just felt quicker. Going from
512mb to 1gb made the biggest
differance - playing any modern game (HL2, Doom3, Far Cry etc on WinXP) with
less than 1gb and you
are bound to get plenty of Hard Disk access and stuttering. But playing
those games on a Duron 1800 isnt
that great either. But Im not sure you have a Duron - theres no such chip as
an Applebred - if you mean
Thoroughbred then thats a Athlon XP1800 you have. Use this program to check
http://www.cpuid.org/cpuz.php - it'll also diagnose your RAM and tell you
its CAS speed.

I have a XP2400 (the fastest CPU that board can support) with 1gb DDR
running at the stock 133mhz
like PC2100 even though its PC2700 and a Radeon 9700. I can play HL2 at
1024x768 High settings
and its smooth. Doom 3 I use 800x600 medium settings and Far Cry 1024
med/high settings works great.
I never worry about resolutions higher than 1024 since I use an old CRT
monitor - a Sony Trinitron tube
with flat screen that looks just fine.

When I had just 512mb of RAM I was getting plenty of Hard Disk access during
games that causes that
stuttering effect and a cheap option that helped a lot was putting an old
Hard Drive back in my system.
I had a 120gb new drive with everything on including the pagefile. I put the
old drive in as a slave drive
or D - formatted it - and put the pagefile on that instead of the C drive -
at a fixed size of 2gb.
That way when my RAM was used up and virtual RAM was being used there were 2
drive heads handling
the movement of data instead of just one and that reduced the stuttering
effect noticeably. Maybe this is an option
you can consider?

Hope this helps.

Ben

 

[Jon D]

But Im not sure you have a Duron - theres no such chip as
an Applebred -

Definitely an Applebred. See

http://www.madshrimps.be/printart.php?articID=106

"The Applebred is the new revision of the Duron series from AMD. It
is a tuned down Thoroughbred B CPU"

 

[Jon D]

On Wed 27 Jul 2005 14:55:22, Cuzman wrote:

Jon D wrote:

" QUESTION ONE. What speed DIMM memory would work well with my
Via266/Duron1800 and yet still be good to use with a faster
processor later this year which will probably be a mid-power
socket 939 (and some mobo chipset which I haven't decided on
yet)? Is PC2700 too slow? "

You need PC3200 for any socket 939 CPU.


" QUESTION TWO. How fast does the bus on my mobo/cpu actually
run these devices at:
(a) the "133/266 MHz FSB" on the cpu
(b) the bus on 133 MHz SD-RAM
(c) suitable DDR in Q.1 (PC2700 ??)
(d) the PCI bus. "

These two articles explain all the relevant frequencies:
http://www.tweakfactor.com/articles/tweaks/neoocguide/3.html
http://arstechnica.com/paedia/r/ram_guide/ram_guide.part3-1.html

Nice links. Thank you. From reading your links and also Wes
Newell's page ("The Real FSB") I think I can see where I was just not
getting started off on a proper understanding.

I had seen the spec for the FSB of some AMD cpu stated in some places
as 100 MHz (or 133 MHz or whatever) and then I had seen the specs for
the same chip but with double the FSB value - ie 200 (or 266 or
whatever).

The single/lower value seems to be the actual clock speed of the FSb
but the double/larger value is the Data Rate. And that term is
nominal because, so it seems, in the original designation there was
no reference by AMD to MHz. Other (later?) AMD documents seem to
contain the term MHz, for example http://tinyurl.com/ytjqq

I guess it's all a bit like the Athlon model numbers with the plus
sign after them: the cpu does not run at that speed but was
originally a guideline of the cpu's claimed speed when comparing
Intel chips.

The FSB of your CPU, chipset and SDRAM is 133.33r MHz. PC2100
DDR SDRAM has the same bus rate as PC133 SDRAM, but is called
DDR266 because it can transfer data on both the rising and
falling edge of the clock cycle. It doesn't actually double the
effective bus rate of 133.33r MHz, and the claims of it
operating at 266.66r MHz are arguably just marketing speak.

What you say is almost the same as I just wrote exept that the AMD
document I link to above claims the Duron's FSB is the higher/double
rate but that is pretty misleading if SD-RAM is used which IIRC is
all that was available for the early Duron.

The PCI and AGP bus work on dividers of the motherboard chipset
bus. When operating a chipset bus of 133.33r MHz, your PCI bus
will work on a divider of 1/4, equalling 33.33r MHz. Your
chipset bus can also operate at 100 MHz with slower processors,
from which the PCI bus will operate on a divider of 1/3, also
equalling 33.33r MHz. Your motherboard's AGP bus can operate at
AGP4x, four times the speed of the PCI bus, thus equalling the
chipset bus of 133.33r MHz.

Useful. Thanks.

 

[Jon D]

-- trimmed --

On Wed 27 Jul 2005 21:21:36, Wes Newell wrote:

See the Real Front Side Bus in link in sig line.

Good article of yours. Thank you!


-- snip --

If buying today, you should buy the fastest reasonably priced
ram. I'd say that's PC3200 which is rated for a 200MHz bus
(DDR400). However, you can use ram as slow as PC2100 (133MHz
DDR266) in both your current board and most/some A64 boards.
Buying the ram today won't help your current system much at all.
Your delima is what will ram prices be later on when you
actually need the DDR ram. Ram is cheap now, but will it be
cheaper later????


133MHz clock. DDR266.


133MHz clock


133MHz clock DDR266, but don't think that will improve
performance by a big margin. It won't. Approximately 90% of CPU
data request are serviced by the CPU cache and the speed of the
external ram has very little to do with it. At most I would
guess you'd get a 5% overall performance increase over standard
sdram. You also need to remember that the ram controller is in
the chipset and all the ram data must share the FSB path to the
CPU, which is DDR even with SDR ram.

It should be 33MHz on any board, but it will go higher if you
overclock the FSB and your MB doesn't have a PCI lock. And yours
doesn't.

Wes. how do you know my mobo doesn't have a PCI lock? Are
you referring to the BIOS setting "Auto Detect DIMM/PCI Clk"?

So how do I use this setting to my advantage?

Do I need to disable the auto detect in that setting (i.e. say no
to that setting) and then vary the "CPU Host Clock" value?

I am sure I have got noticeable improvements from varying the "CPU
Host Clock" value but leave the DIMM/PCI Clock setting on AUTO.
Could this have been possible?

 

[Jon D]

On Thu 28 Jul 2005 09:03:51, Sleepy wrote:

If you put in PC3200/DDR400 it will only run at the stock speed
of 133mhz (x2 is 266mhz which is the speed of PC2100/DDR266) but
you could overclock the FSB a little if you put in that RAM -
you do it in the Bios and if you put it up to say 140mhz your
CPU would perform like a 1900 or 2000. Every component connected
to that board would run a little faster and of course a little
hotter so make sure your case has decent cooling if you
do that.

Your overclocking potential is limited on that board because you
can only raise the CPU core
voltage by up to .75v - a real overclockers board would allow
about 3x that adjustment.

I went from SDRAM to DDR on this board and it made a noticeable
differance - I never benchmarked
it but most ppl say the differance is 10% - it just felt
quicker. Going from 512mb to 1gb made the biggest
differance - playing any modern game (HL2, Doom3, Far Cry etc on
WinXP) with less than 1gb and you
are bound to get plenty of Hard Disk access and stuttering. But
playing those games on a Duron 1800 isnt
that great either. But Im not sure you have a Duron - theres no
such chip as an Applebred - if you mean
Thoroughbred then thats a Athlon XP1800 you have. Use this
program to check http://www.cpuid.org/cpuz.php - it'll also
diagnose your RAM and tell you its CAS speed.

I have a XP2400 (the fastest CPU that board can support) with
1gb DDR running at the stock 133mhz
like PC2100 even though its PC2700 and a Radeon 9700. I can play
HL2 at 1024x768 High settings
and its smooth. Doom 3 I use 800x600 medium settings and Far Cry
1024 med/high settings works great.
I never worry about resolutions higher than 1024 since I use an
old CRT monitor - a Sony Trinitron tube
with flat screen that looks just fine.

When I had just 512mb of RAM I was getting plenty of Hard Disk
access during games that causes that
stuttering effect and a cheap option that helped a lot was
putting an old Hard Drive back in my system.
I had a 120gb new drive with everything on including the
pagefile. I put the old drive in as a slave drive
or D - formatted it - and put the pagefile on that instead of
the C drive - at a fixed size of 2gb.
That way when my RAM was used up and virtual RAM was being used
there were 2 drive heads handling
the movement of data instead of just one and that reduced the
stuttering effect noticeably. Maybe this is an option
you can consider?

Hope this helps.

Ben

Ben/Sleepy, thank you very much for helping me further with this.
You make some valuable points. The thing I am not so sure about is
the query I raised with Wes in this same thread in my message:
<
Maybe you know the answer to what I ask from your own experience.
Wes observed that I didn't have a PCI Lock and I asked:

Are you referring to the BIOS setting "Auto Detect DIMM/PCI Clk"

If so then how do I use that setting to my advantage?

Do I need to disable the auto detect in that setting (i.e. say no
to that setting) and then vary the "CPU Host Clock" value?

I'm sure I have got noticeable improvements from varying the "CPU
Host Clock" value but leave the DIMM/PCI Clock setting on AUTO.
Could this have been possible?

 

[Wes Newell]

Definitely an Applebred. See

http://www.madshrimps.be/printart.php?articID=106

"The Applebred is the new revision of the Duron series from AMD. It
is a tuned down Thoroughbred B CPU"

Hogwash. It's just a Tbred A or B core with the cache size set for 64k.
Reference AMD doc Processor Model 8 Data Sheet, 25848.pdf

Calling it Applebred or wheat bread won't change those facts. New cores
ALWAYS have new CPUID's. Now what I heard was that the Applebred was a
Barton core with only 64K cache enabled. So take your pick. In any case,
it is not a new core, just a new nickname, and if you get an older Tbred A
core, you won't be able to overclock it much either.

 

[kony]

Ben/Sleepy, thank you very much for helping me further with this.
You make some valuable points. The thing I am not so sure about is
the query I raised with Wes in this same thread in my message:
<
Maybe you know the answer to what I ask from your own experience.
Wes observed that I didn't have a PCI Lock and I asked:

Not having a PCI lock merely means that if you choose to
overclock by raising the FSB, the resulting PCI bus speed
will be divided by 4. For example, if you manually set your
board to use 155MHz FSB (if the bios even allows that), then
the resulting PCI bus speed would be: 155/4 = 38.75MHz.
That's usually too high a PCI bus speed and would be
instable.

Are you referring to the BIOS setting "Auto Detect DIMM/PCI Clk"

No that setting has no effect on the (lack of) PCI lock.
Instead it causes the board to read and use the memory SPD
programmed values on your memory modules, then use
bios-contained logic to automatically set the memory bus
frequency and timings. It's meant to be an "automatic" way
of setting the system parameters without the users needing
to know how to set it themselves. The alternative to "auto"
(automatic) setting is manually setting it. Do that if you
know what the settings should be. It should be same speed
as the FSB, and the correct memory timings that your memory
is spec'd to be able to use. Then you would need to
extensively test memory stability.

It's really not worth changing all these settings, at most
it would get you a very tiny performance increase, but also
has the potential to make system slower if set incorrectly.
Any kinds of changes made are a very minor impact on system
performance compared to something as simply as switching
from a Duron to Athlon CPU.

If so then how do I use that setting to my advantage?

Being "auto" is how you should leave it. These settings
should not be changed unless you know they need changed,
which you do not.

If you were to download and run "CPU-Z", it will show you
what your programmed memory timings are and also the
actually-used memory timings. You can compare these to see
if your memory is being ran at optimal timings. As far as
oveclocking, that is a try-it-and-see scenario, you would
have to make guesstimations about how fast the memory might
run. It's not worth the risks on that system.

Do I need to disable the auto detect in that setting (i.e. say no
to that setting) and then vary the "CPU Host Clock" value?

You do not "need" to do anything if the system is running
stabily. Test it with memtest86. You could try increasing
the CPU host clock value but it seems (based on your
question) that you need a more basic understanding of
overclocking before making such changes. There are various
tutorials on the 'net, Google search for some.

I'm sure I have got noticeable improvements from varying the "CPU
Host Clock" value but leave the DIMM/PCI Clock setting on AUTO.
Could this have been possible?

It's possible. That doesn't mean it's true. Benchmarks
would be needed to demonstrate the effect of any settings
changes.

 

[Sleepy]

On Thu 28 Jul 2005 09:03:51, Sleepy wrote:



Ben/Sleepy, thank you very much for helping me further with this.
You make some valuable points. The thing I am not so sure about is
the query I raised with Wes in this same thread in my message:
<
Maybe you know the answer to what I ask from your own experience.
Wes observed that I didn't have a PCI Lock and I asked:

Are you referring to the BIOS setting "Auto Detect DIMM/PCI Clk"

If so then how do I use that setting to my advantage?

Do I need to disable the auto detect in that setting (i.e. say no
to that setting) and then vary the "CPU Host Clock" value?

I'm sure I have got noticeable improvements from varying the "CPU
Host Clock" value but leave the DIMM/PCI Clock setting on AUTO.
Could this have been possible?

Yep - just alter the CPU Host/ PCI Clock setting from 133mhz to 140mhz. Boot
up and you should see the CPU noted as running faster in the initial boot up
screen. Use that program I mentioned (CPU-Z) in Windows and it'll confirm
the higher CPU and RAM speeds. With one of my sticks of RAM I managed 148mhz
which made my XP2400 perform like an XP2600 (or maybe higher) but the other
stick was unstable cause I couldnt run the TRAS setting low enough. If its
unstable at 140mhz then raise the Core Voltage Regulator setting on the same
Bios page. Use a temperature monitoring program like Via hardware Monitor or
Motherboard Monitor and remember 40s are good - 50s are okay but if you hit
60c forget it and run at normal speeds.