View Full Version : PC2100 CAS2 or PC2700???

10-24-02, 03:03 AM

I recently upped my system performance quite considerably by removing half of my RAM - which was nice if unexpected!!!

The system had been running with 512MB PC2100 DDR RAM with a CAS latency of 2.5 and scoring a consistent 9000ish points in 3d Mark. Last weekend I lent half my memory to a friend and was quite surprised to see my 3d Mark score shoot up to 10216.

Now I'm a little confused as to what I should buy to keep the performance but restore my loading times - what would work better either PC2700 DDR CAS 2.5 or PC2100 CAS 2.0

I unfortunatley can't afford to lay out for PC2700 DDR CAS 2.0 so which would give the better performance of the two mentioned above.

As my motherboard doesn't appear to support anything beyond a 2600+ it seems unlikely that my FSB will go above 266Mhz so 333Mhz RAM may not be an investment for the future.

Hope this makes sense!


10-24-02, 03:08 AM
Most of the PC2700 CL2,5 memory sticks can run at CL2 (or even better 2-2-5-2-1 timings) at 166MHz. They WILL run 133MHz with the fastest timings for sure. I'd go for the PC2700 stick.

10-24-02, 03:55 AM
Great - hadn't thought of that possibility.

Only other question is whether there is really any performance gain from 266 to 333Mhz ram as it will stop the memory being synchronous with the cpu.



10-24-02, 10:12 PM
I believe there are performance gains to be had by using the faster DDR. The pentium4 in particular is supposed to make use of that extra bandwidth.

10-24-02, 10:18 PM
the most important thing is whether your processor will be running at a faster fsb to make use of the 2700, and at better cas settings.

10-25-02, 01:38 AM
Originally posted by thcdru2k
the most important thing is whether your processor will be running at a faster fsb to make use of the 2700, and at better cas settings.
bingo. if the FSB only runs a 266, you have no plans of overclocking the FSB, and the memory cannot be run at CL2, then the DDR266 will be faster.

10-25-02, 02:21 AM
Thank you everyone!

10-31-02, 07:43 AM
Well I went out and bought some PC2700 RAM planning to run it at 133 CL2 or mess about with 166 CL2.5/CL2 and guess what.


It didn't matter to my system whether it was running at 133 CL2/166 CL2.5/166 CL2 the memory bandwidth test from SiSoft reported nearly identical results!!!!

On a related note for anyone reading from the UK PCWorld are being their normal dickheaded self and selling 512MB of PC2700 RAM for 130 pounds. The chips are WinBond BH-8 and more than capable of running at 166mhz with CAS2 timings (SPD only reports CAS2.5 but if you force it it'll work fine)

Praise be to dickhead hardware stores who don't know what they are selling.


11-01-02, 07:11 AM
I don't think there is really that much of a price difference in the 2.0 vs. the 2.5 really.