would you rather have 1GB of ddr 266 or 512 MB ddr 400?

  • Thread starter Thread starter Mr Rafal Rozborski
  • Start date Start date
would you rather have 1GB of ddr 266 or 512 MB ddr 400?
Click to expand...

Why are we taking this poll?

It can't be a serious question because there is no context,
no description of the system it'll be in or the use of that
system.

The generic answer is that your memory bus should be at same
speed as the FSB or +33MHz may be marginally better on some
Intel/P4 supportive chipsets or with use of integrated
video. Only deviate from that if you have particular uses
of the system that need significantly more than 512MB
memory. This generic answer may not be quite accurate since
it cannot be applied to the system or use.
 
Mr Rafal Rozborski said:
would you rather have 1GB of ddr 266 or 512 MB ddr 400?
Click to expand...

thats easy - 1gb. I take it you have 1 stick of each and and are pondering
whether to use both sticks at the slower speed or the one faster stick on
its own. loads of games now really need 1gb.
 
The generic answer is that your memory bus should be at same
speed as the FSB or +33MHz may be marginally better on some
Intel/P4 supportive chipsets or with use of integrated
video. Only deviate from that if you have particular uses
of the system that need significantly more than 512MB
memory. This generic answer may not be quite accurate since
it cannot be applied to the system or use.
Click to expand...

I didn't know that. I have 1.5GB in my Athlon XP 2400. I use the computer
for all sorts, but need lots of RAM for large photo and multimedia work. The
CPU is 166MHz (FSB 266), but the RAM runs at 166MHz, DDR333, so is set to
FSB + 33MHz. This is the default setting for this motherboard (Soltek
SL75-DRV5). Should I turn the RAM speed down to match the CPU frequency? Why
would the motherboard offer this option if it is not faster? Why is slower
memory faster?
 
I didn't know that. I have 1.5GB in my Athlon XP 2400. I use the computer
for all sorts, but need lots of RAM for large photo and multimedia work. The
CPU is 166MHz (FSB 266), but the RAM runs at 166MHz, DDR333, so is set to
FSB + 33MHz.
Click to expand...

Presumably you mean CPU is 133MHz (DDR266).

This is the default setting for this motherboard (Soltek
SL75-DRV5). Should I turn the RAM speed down to match the CPU frequency? Why
would the motherboard offer this option if it is not faster? Why is slower
memory faster?
Click to expand...

There are multiple busses, and on athlon both mem and fsb
are DDR, double data rate. The throughput of the northbridge
to CPU (FSB) is the bottleneck. Raising the memory bus
speed to an async setting adds latency because that is
inherant in different bus speeds. IF the FSB were at a
higher data rate (not necessarily clock speed), for example
the P4 has quad-pumped (4X) bus instead of Athlon XP's
Double Data Rate (2X) bus, then it would not be a bottleneck
anymore and exploiting the higher throughput of the FSB
might be worthwhile even with the added latency. With the
integrated video, data to/fro northbridge/memory is used as
a frame buffer and with integrated video being more of a
bottleneck to video uses (and consuming bandwidth
continually) it will then help to have the higher mem bus.

How much of a difference you'd see can also depend on the
default and changed bus speed as it allows for a memory
timings change. Generally dropping the mem bus MHz will
allow tigher (lower numbered) timings and will be of
benefit. You should try it with the synchronous (133MHz)
memory bus and use CPU-Z (Google will find it) to check the
before and after memory timings the board sets (note that
CPU-Z will show both the SPD-programmed timings and those
the board is actually using, both sets of info are useful).

The difference is not a lot though, and your particular make
and model of board may determine if it's stable at any
particular timings per bus speed with any particular
module... I'm impressed that your board (which seems to be
KT333 based?) can even run 166MHz memory with 1.5GB
installed.
 
Mr Rafal Rozborski said:
would you rather have 1GB of ddr 266 or 512 MB ddr 400?
Click to expand...


My system is: Pentium 4 630 (3.00GHz) FSB 199.5 Bus speed 798.1
I need to choose between DDR 266 4 sticks of 256 MB each vs 1 stick of 512
MB DDR 400. Computer used for everyday tasks ... I would like to get best
performance when running latest games.
 
My system is: Pentium 4 630 (3.00GHz) FSB 199.5 Bus speed 798.1
I need to choose between DDR 266 4 sticks of 256 MB each vs 1 stick of 512
MB DDR 400. Computer used for everyday tasks ... I would like to get best
performance when running latest games.
Click to expand...


Why would you "need" to choose?
Both are poor options. Latest games benefit greatly from
both high memory bus speed AND more than 512MB of memory.
Since each game places slightly different demands on a
system, it's even possible that one game might benefit more
from 1GB of slow memory while another game benefits more
from 512MB at the correct PC3200 DDR400 speed. Further,
having 4 x 256MB modules is likely going to cause the memory
timings to be raised for stability reasons so it's even
slower than DDR266, PC2100 memory would normally be.

The goal here should be to add another 512MB module of
PC3200 (DDR400) memory so you have 2 x 512MB, 1GB total of
PC3200. Sell the 1GB of DDR266 if you already have it, to
offset the cost of more PC3200 memory.
 
kony said:
Presumably you mean CPU is 133MHz (DDR266).
Click to expand...

Typo! Yes CPU is 133MHz, RAM is 166MHz at present.
There are multiple busses, and on athlon both mem and fsb
are DDR, double data rate. The throughput of the northbridge
to CPU (FSB) is the bottleneck. Raising the memory bus
speed to an async setting adds latency because that is
inherant in different bus speeds. IF the FSB were at a
higher data rate (not necessarily clock speed), for example
the P4 has quad-pumped (4X) bus instead of Athlon XP's
Double Data Rate (2X) bus, then it would not be a bottleneck
anymore and exploiting the higher throughput of the FSB
might be worthwhile even with the added latency. With the
integrated video, data to/fro northbridge/memory is used as
a frame buffer and with integrated video being more of a
bottleneck to video uses (and consuming bandwidth
continually) it will then help to have the higher mem bus.

How much of a difference you'd see can also depend on the
default and changed bus speed as it allows for a memory
timings change. Generally dropping the mem bus MHz will
allow tigher (lower numbered) timings and will be of
benefit. You should try it with the synchronous (133MHz)
memory bus and use CPU-Z (Google will find it) to check the
before and after memory timings the board sets (note that
CPU-Z will show both the SPD-programmed timings and those
the board is actually using, both sets of info are useful).

The difference is not a lot though, and your particular make
and model of board may determine if it's stable at any
particular timings per bus speed with any particular
module... I'm impressed that your board (which seems to be
KT333 based?) can even run 166MHz memory with 1.5GB
installed.
Click to expand...

This board is indeed KT333. At the time, it was one of the best I could get
find for overclocking features. I always planned to overclock, but I have
never actually bothered!. I figure an extra 5% is not really worth the extra
stress on the CPU. Instead, I have the processor running at normal speed
settings, but I have under-volted it and replaced all standard HSFs with
passives and designed careful airflow round the case so it all runs silently
and cool.

I have been running this M/B at CPU133 and RAM166 (CL2.5) for about 2 years
(maybe longer) now. I used to use 2GB RAM (1G+512+512), but the 3rd DIMM
slot on the board packed up about 6 months ago, so I am down to 1.5GB with a
spare 512 DDR333. There was a thread a few days ago about DIMM slots failing
and someone told me then (perhaps you?) that the KT333 chipsets are poor at
handling RAM in more than 2 slots.

Anyway, I've only just read your reply, so I haven't had a chance to test
the lower memory speed, but I would like to try it and find out if there is
much real-world difference - can you recommend a good benchmark tool for a
before and after speed test of CPU+RAM? I have a demo version of SiSoft
Sandra on CD if that is worth trying?
 
I have been running this M/B at CPU133 and RAM166 (CL2.5) for about 2 years
(maybe longer) now. I used to use 2GB RAM (1G+512+512), but the 3rd DIMM
slot on the board packed up about 6 months ago, so I am down to 1.5GB with a
spare 512 DDR333. There was a thread a few days ago about DIMM slots failing
and someone told me then (perhaps you?) that the KT333 chipsets are poor at
handling RAM in more than 2 slots.
Click to expand...

Yes, they seem most stable with 3 or fewer banks of memory
(which would be at most, 1GB module plus single-sided 512MB
module).

Anyway, I've only just read your reply, so I haven't had a chance to test
the lower memory speed, but I would like to try it and find out if there is
much real-world difference - can you recommend a good benchmark tool for a
before and after speed test of CPU+RAM? I have a demo version of SiSoft
Sandra on CD if that is worth trying?
Click to expand...


Sandra will give you a number though it's not idea as it's
too isolated. Even so, as the difference is already slight
the less isolated the test the more difficult it would be to
see statistically signficant differences. What are your
typical, most demanding uses of the system? It would be
idea to be able to benchmark in the most applicable scenario
possible.

When you pulled out that 3rd module, were you still trying
to run at 166MHz then? If so, you might even find that
dropping to 133MHz would allow adding the 3rd module back,
although it might cause the bios to raise (slow down) memory
timings more... part of why CPU-Z is useful to see what the
board is actually running, especially if bios is set to
"auto" mode it may ignore the SPD-programmed timings and set
something more conservative.
 
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