DDR PC2700 and PC3200

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A few months back, I bought a Biostar iDEQ 210v mini PC
http://www.biostar.com.tw/products/barebone/ideq/210v/index.php3
to replace my old one after the mother board gave up the ghost. I
bought this particular one as I could use my original CPU, an Athlon
XP1800. I also bought 512 meg DDR PC3200 memory. Since I had 512 meg
of PC2700 out of the old computer, I though, "Hmm, what if?" I put it
in, took it out, shook it all about, but couldn't tell any difference
in the speed of the computer, and had no errors at all. Both memory
sticks have been in now for about three months with no seemingly
adverse effects. So my question is, what *should* I be experiencing by
installing the slower memory?
 
A few months back, I bought a Biostar iDEQ 210v mini PC
http://www.biostar.com.tw/products/barebone/ideq/210v/index.php3
to replace my old one after the mother board gave up the ghost. I
bought this particular one as I could use my original CPU, an Athlon
XP1800. I also bought 512 meg DDR PC3200 memory. Since I had 512 meg
of PC2700 out of the old computer, I though, "Hmm, what if?" I put it
in, took it out, shook it all about, but couldn't tell any difference
in the speed of the computer, and had no errors at all. Both memory
sticks have been in now for about three months with no seemingly
adverse effects. So my question is, what *should* I be experiencing by
installing the slower memory?
Click to expand...


Depends. If the 2700 you put in forced the system to go down to
333/166 then you have a slower system. You know your 3200 stick is set
down to 2700.

If your 2700 is good enough to be stable at 3200 then you have no
problems. You might want to run memtest86 for a few hours to see if
any errors come up though.

I bought two sticks of 2100 crucial on an old system. I tested them
when I first bought a nforce2 with a barton 2500 I Oced to 3200. The
2100 sticks ran fine at 400/200. I had already bought two 512 sticks
of3200 so I didnt use those 2100 at 3200. Later I tried the 2100
sticks in my nforce4 board and a nforce3 and they didnt work at 3200.
 
Depends. If the 2700 you put in forced the system to go down to
333/166 then you have a slower system. You know your 3200 stick is set
down to 2700.

If your 2700 is good enough to be stable at 3200 then you have no
problems. You might want to run memtest86 for a few hours to see if
any errors come up though.

I bought two sticks of 2100 crucial on an old system. I tested them
when I first bought a nforce2 with a barton 2500 I Oced to 3200. The
2100 sticks ran fine at 400/200. I had already bought two 512 sticks
of3200 so I didnt use those 2100 at 3200. Later I tried the 2100
sticks in my nforce4 board and a nforce3 and they didnt work at 3200.
Click to expand...
There's been no noticable slowdown from using the CPU in the other
computer. Maybe this set up would be faster with all PC3200 memory,
but I do know there's less HD activity when I am editing audio, so
I'll settle for slower, but more, memory, and spend the savings on
something more important, like beer. :)

Thanks for the reply.
 
A few months back, I bought a Biostar iDEQ 210v mini PC
http://www.biostar.com.tw/products/barKM400)ebone/ideq/210v/index.php3
to replace my old one after the mother board gave up the ghost. I
bought this particular one as I could use my original CPU, an Athlon
XP1800. I also bought 512 meg DDR PC3200 memory. Since I had 512 meg
of PC2700 out of the old computer, I though, "Hmm, what if?" I put it
in, took it out, shook it all about, but couldn't tell any difference
in the speed of the computer, and had no errors at all. Both memory
sticks have been in now for about three months with no seemingly
adverse effects. So my question is, what *should* I be experiencing by
installing the slower memory?
Click to expand...

Athlon XP1800 uses 133MHz/DDR266 FSB. The optimal memory
bus speed for it is 133MHz/PC2100, with the memory timings
lowered as much as possible. In other words, take a random
PC3200 module rated as 3,4,4,8 timings and run it at PC2100
speed and it'll probably do 2.5,3,3,x or 2,3,3,x or maybe
even 2,2,2,x.

Above I used "X", because on some boards like nForce2, the x
is a faster timing at around 9-11, but on yours (KM400),
keeping it lower like 6 would be better.

HOWEVER, your board has integrated video. IF you are using
the integrated video instead of a separate video card, the
above settings are no longer optimal. You take a slight
performance hit (sometimes trivial) to use the asynchronous
memory bus for CPU performance, but your integrated video
benefits from the higher memory bus speed. So with a 133MHz
FSB CPU, your memory bus would be set to 166MHz, PC2700
speed so long as you use the integrated video.

So your upper target is PC2700 spec'd speed, 166MHz mem bus.
You might as well have two PC2700 modules then, as your
PC3200 module will simply be running at PC2700 speed either
way- with it alone or with both modules installed. "Might
as well" doesn't mean you need to change anything, only that
given the CPU and chipset, the PC3200 is only potential you
aren't able to exploit at the moment... except that as with
the case of the memory downclocked to PC2100 above, PC3200
memory running at PC2700 speed may also allow tigher (lower)
memory timings, though your PC2700 module, if older, may
already be the limit on how fast the timings can be set.

In other words, it's fine as-is, probably not worth trying
to change.
 
Your system's motherboard was never able to run at the PC3200 RAM's native
speed. So you have always been running at the slower speed, including after
you put the PC2700 RAM in.
 
Your system's motherboard was never able to run at the PC3200 RAM's native
speed. So you have always been running at the slower speed, including after
you put the PC2700 RAM in.
Click to expand...

Most of this technical stuff means nothing whatsoever to me, so please
bear with me while I show my ignorance.

Are you saying that the MB is physically incapable of running the
PC3200 at it's native speed? Or is it because I am using the XP1800
CPU? If not the latter, why does the MB have DDR400 slots? Also, would
there be any point in me upgrading to the XP3200, which is the fastest
CPU the board will take? Not using the PC2700 in that case, of course.
 
Athlon XP1800 uses 133MHz/DDR266 FSB. The optimal memory
bus speed for it is 133MHz/PC2100, with the memory timings
lowered as much as possible. In other words, take a random
PC3200 module rated as 3,4,4,8 timings and run it at PC2100
speed and it'll probably do 2.5,3,3,x or 2,3,3,x or maybe
even 2,2,2,x.

Above I used "X", because on some boards like nForce2, the x
is a faster timing at around 9-11, but on yours (KM400),
keeping it lower like 6 would be better.

HOWEVER, your board has integrated video. IF you are using
the integrated video instead of a separate video card, the
above settings are no longer optimal. You take a slight
performance hit (sometimes trivial) to use the asynchronous
memory bus for CPU performance, but your integrated video
benefits from the higher memory bus speed. So with a 133MHz
FSB CPU, your memory bus would be set to 166MHz, PC2700
speed so long as you use the integrated video.

So your upper target is PC2700 spec'd speed, 166MHz mem bus.
You might as well have two PC2700 modules then, as your
PC3200 module will simply be running at PC2700 speed either
way- with it alone or with both modules installed. "Might
as well" doesn't mean you need to change anything, only that
given the CPU and chipset, the PC3200 is only potential you
aren't able to exploit at the moment... except that as with
the case of the memory downclocked to PC2100 above, PC3200
memory running at PC2700 speed may also allow tigher (lower)
memory timings, though your PC2700 module, if older, may
already be the limit on how fast the timings can be set.

In other words, it's fine as-is, probably not worth trying
to change.
Click to expand...

I'm afraid most of the above whooshed straight over my head. Maybe I
should start doing some reading up, though maybe I don't really need
to know. Just to point out I don't use the integral video, I use a
rather old 128 meg NVIDIA GeForce MX 440, if that makes any
difference.

If I should upgrade to an XP3000, (not XP3200 as I said in my reply to
DaveW), and remove the PC2700, would the whole setup then be working
at optimal performance?
 
If I should upgrade to an XP3000, (not XP3200 as I said in my reply to
DaveW), and remove the PC2700, would the whole setup then be working
at optimal performance?
Click to expand...

Yeah that was the point .

A) Your old CPU is designed use a lower FSB setting so you get
virtually no improvement by using higher rated memory with your old
processor

B) Your motherboard can go up to 400 FSB so it can use 3200 IF you had
a processor that can use 3200 memory.

Your memory 3200 is OK and your motherboard system can be set to use
3200 at 400 FSB. All you have to do is get a processor that runs at
400 FSB. The thing is I dont see a lot of 3000 400 FSB athlons around
anymore. Ive read AMD stopped making socket A processors so many of
them are drying up so Id think about getting one pretty soon.

Now if if you got a 400 FSB processor

You would have :

A) Processor that can use 3200 memory
b) Motherboard that can run at 400 FSB
c) ONE stick of 3200 memory

The other 2700 stick of memory will either force your system to run at
a lower FSB if it cant work at 3200. Some memory can run higher than
its spec but others cant. Or itll make you system flakey.

If you put both in and it still seems to run and boot up --- not hang
or get blue screens or reboot etc then you should test it with
memtest86 a free download util that test for any memory errors.
I think theres the Circuit City 512 megs of Kingston DDR for 25 bucks
after a hefty rebat this week until Sat. Thats if you live in the US.
 
Most of this technical stuff means nothing whatsoever to me, so please
bear with me while I show my ignorance.

Are you saying that the MB is physically incapable of running the
PC3200 at it's native speed? Or is it because I am using the XP1800
CPU?
Click to expand...

It is physically capable, as it does support CPUs with 166
or 200MHz (DDR400) FSB, and with that a synchronous (same
speed) memory bus. It IS because your current CPU is XP1800
and therefore, being an XP1800 it determines the FSB speed
the motherboard uses.
If not the latter, why does the MB have DDR400 slots? Also, would
there be any point in me upgrading to the XP3200, which is the fastest
CPU the board will take? Not using the PC2700 in that case, of course.
Click to expand...

An XP3200 would be a significant performance upgrade of
course, BUT today buying one might be a bad idea because the
cost increase might be seen as getting you partway towards a
new motherboard/cpu/memory combination that would be even
faster than an XP3200. So, it all depends on how fast you
want to go, how much $ that's worth. There is the second
benefit to upgrading to the Xp3200, that by keeping
everything else the same, you need not do anything (like
repair installation) to the operating system, the new CPU
would install and system runs like nothing changed (except a
little faster). I can't make that call for you though,
personally I wouldn't buy an XP3200 CPU today but then I'm
not using an XP1800. As always, consider your most
demanding tasks and what that task(s) have as most
significant bottlenecks, then that'll guide you to the best
upgrade for any particular budget.
 
It is physically capable, as it does support CPUs with 166
or 200MHz (DDR400) FSB, and with that a synchronous (same
speed) memory bus. It IS because your current CPU is XP1800
and therefore, being an XP1800 it determines the FSB speed
the motherboard uses.


An XP3200 would be a significant performance upgrade of
course, BUT today buying one might be a bad idea because the
cost increase might be seen as getting you partway towards a
new motherboard/cpu/memory combination that would be even
faster than an XP3200. So, it all depends on how fast you
want to go, how much $ that's worth.
Click to expand...

As always, money is the main consideration, though, for what I use the
computer for, even a lesser system than the one I have would be
adequate. I stopped playing games around the time of the original Half
Life, and that got me off the constant upgrade cycle. Now I only
upgrade when I can no longer buy parts to repair whatever I am using
at present. Today, all I use it for is Usenet, ICQ, watching
documentaries, listening to music, and the occasional vinyl rip, so
this set up should be good for quite a while yet.
There is the second
benefit to upgrading to the Xp3200, that by keeping
everything else the same, you need not do anything (like
repair installation) to the operating system, the new CPU
would install and system runs like nothing changed (except a
little faster). I can't make that call for you though,
personally I wouldn't buy an XP3200 CPU today but then I'm
not using an XP1800. As always, consider your most
demanding tasks and what that task(s) have as most
significant bottlenecks, then that'll guide you to the best
upgrade for any particular budget.
Click to expand...

Many thanks for all the replies. At least I've learned a little,
seeing as my hardware knowledge tailed off a little when 5.25 drives
were phased out. :)
 
Yeah that was the point .

A) Your old CPU is designed use a lower FSB setting so you get
virtually no improvement by using higher rated memory with your old
processor

B) Your motherboard can go up to 400 FSB so it can use 3200 IF you had
a processor that can use 3200 memory.

Your memory 3200 is OK and your motherboard system can be set to use
3200 at 400 FSB. All you have to do is get a processor that runs at
400 FSB. The thing is I dont see a lot of 3000 400 FSB athlons around
anymore. Ive read AMD stopped making socket A processors so many of
them are drying up so Id think about getting one pretty soon.

Now if if you got a 400 FSB processor

You would have :

A) Processor that can use 3200 memory
b) Motherboard that can run at 400 FSB
c) ONE stick of 3200 memory

The other 2700 stick of memory will either force your system to run at
a lower FSB if it cant work at 3200. Some memory can run higher than
its spec but others cant. Or itll make you system flakey.
Click to expand...

Many thanks for the explanation.
If you put both in and it still seems to run and boot up --- not hang
or get blue screens or reboot etc then you should test it with
memtest86 a free download util that test for any memory errors.
I think theres the Circuit City 512 megs of Kingston DDR for 25 bucks
after a hefty rebat this week until Sat. Thats if you live in the US.
Click to expand...

I'm in the UK. A quick Google shows I can expect to pay more than
double that price; and rebates, as far as I know, don't exist over
here.
 
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