Windows Performance Index RAM scores

[admuh]

Hi, I'm just wondering how the 2x 1GB 5-5-5-18 2T DDR2-4200(Scores 5.9) in my
mums computer scores more than my 4x1GB 4-3-3-10 1T DDR2-6400(Scores 5.4).
The timings have made no difference to the score when I have changed them and
I can play modern games perfectly. Could it be due to my processor(Core 2 Duo
Quad) or my motherboard(Fatal1ty IN-9 SLI)? An overall rating of 5.4 for my
computer seems a tad low since it's all top of the range components. Thanks
for any help

 

[CJM]

Have a look at what CPU-Z is reporting - see how both sets of RAM are
actually being utilized.

In my experience, increasing my 4GB PC6400 RAM to 6GB PC6400 RAM cause a
drop of 0.2 (5.8 -> 5.6) in the WE Index. I think this was because I'd
dropped from 4-4-4-12 to 5-5-5-18. Tightening the timings a little allowed
me to pull back to 5.7, but I haven't investigated further.

Nevertheless, it seems that beyond a certain amount, quantity is not an
issue, but timings are.

 

[admuh]

Thanks for the reply. My timings are pretty low though, and I dont see why
cheaper, slower ram scores better. 6400 ram should easily be 5.9 really CPU-Z
says what my timings are however its reporting my frequency to be 400mhz (I
take it it's real speed is double though?)

 

[Mark]

It has been seen in some cases that the clock speed of the CPU and the bus
speed of the memory may not be a good match. _Sometimes_ with DDR2-6400, it
is better to slow it down to 667MHz in the BIOS.

 

[Mark]

PS. Sometimes you will find that the memory sold as 800 MHz is only
recognized and runs as 667 MHz unless overclocked. This can be seen in the
BIOS also.

 

[admuh]

Thanks i'll give that a try

PS. Sometimes you will find that the memory sold as 800 MHz is only
recognized and runs as 667 MHz unless overclocked. This can be seen in the
BIOS also.

 

[CJM]

It has been seen in some cases that the clock speed of the CPU and the bus
speed of the memory may not be a good match. _Sometimes_ with DDR2-6400,
it
is better to slow it down to 667MHz in the BIOS.

When overclocking, it is often better to make sure the RAM:FSB ration is
1:1, and hence you often choose to reduce the RAM speed, but in general use,
I've never come across a situation where properly rated RAM is better run at
a lower frequency.

 

[CJM]

PS. Sometimes you will find that the memory sold as 800 MHz is only
recognized and runs as 667 MHz unless overclocked. This can be seen in the
BIOS also.

Again, if something is sold as PC2-6400, it should be corrected rated to run
and 800MHz. Anyone selling PC2-5300 RAM as PC2-6400 RAM on the basis of
overclocking is breaking the law.

However, official DDR2 RAM speeds only go upto 800MHz, so DDR2 RAM that has
a higher rating is outside the official standard - I'm not sure in this case
what SPD information is stored in these chips... is it the highest official
rating (PC2-6400) or its actual rating (PC2-1066 for example).

 

[Mark]

First, PC-6400 is sometimes sold with the following statement on the
package:

Dual-Channel DDR2 800
DDR2 is the next generation memory technology to replace the current DDR.
With the highest speed up to 800MHz, DDR2 memory provides great performance
for 3D graphics and other memory demanding applications.

It's that "up to 800 MHz" you got to watch for. If it is stated this way, or
shown with anything other than 1.8v rating, then it can only be achieved by
overclocking the memory. It may actually be PC-5300-667.

Second, the default FSB speed of your machine may not be 400 MHz. If it's
333 MHz, then your PC-6400-800 will run at 667 MHz.
Fatal1ty IN-9 SLI is factory overclocked. It's default is 333MHz and
overclocked to 375MHz, not 400 MHz and has been reported stable up to
490MHz. But, the factory setting resets the speed on every boot back to
375MHz. This is probably the ding in WEI you are experiencing.

Third, the latency of the memory sticks should be matched. If not, WEI will
use the worst case scenario.

Last, WEI sucks as a performance indication of your machine. Get CPU-Z and
find out what your memory is really doing.
http://www.cpuid.com/download/cpuz_144.zip

 

[admuh]

Well, my timings were 4-3-3-10 1T on CPU-Z and the speed was 800mhz. My RAM
is OCZ SLI 6400, all sticks are at the same. However, I OC'd the RAM to
850Mhz and changed the timings to 4-4-4-12 2T and Vista scored it the same
which seems a bit odd. I think even DDR1 RAM can score higher than 5.4 as
well. I think it's either Vista or my motherboard, unless I have a bandwidth
issue because of the Q6600. Thanks for the suggestions,

 

[Mark]

See my reply to CMJ.
I think it's your motherboard.

 

[admuh]

Well, I had a play with FSB, I put it up to 1200 and my cpu multiplyer to 8x
and my RAM to 800. I got .1 better on the windows performance index
although I still think 5.5 is low. I think it's likely to be a bandwidth
issue although underclocking my cpu to 2.1 didnt change things either (not
even the processor score). Thanks for the help so far

 

[Robert McMillan]

I have a Gigabyte GA-P35-DS4 board with the Q6600@stock and 4gb 800Mhz ram
(2x2gb) running 5-5-5-15 timings and vista is giving me 5.5 as the score.
Just something to compare it to.
Robert

 

[admuh]

Hm, well that should really be getting 5.5 too if my mums 2GB DDR2 4200 gets
5.9. Maybe it's something to do with Quads

 

[Mark]

I'm actually wondering if your computers suffer a ding in performance
because the memory is not faster.
A quad processor has four CPUs trying to access the same memory and may be
reaching a bottleneck on bandwidth due to the memory being limited to 800
MHz. Basically, in your case, the WEI may be right in implying there is room
to grow. The quad processor should be capable of a particular bandwidth for
I/O to memory and the memory bus is reaching it's limit before the CPUs are
reaching their limit.

I have a two core system and it gets a WEI of 5.9 on memory (800 MHz). But,
in my case, that's the best it will ever do based on the CPUs bandwidth
availability.