So WinXP doesn't know how much L2 cache our CPUs have...

[Megatomic]

I was reading an optimization guide a few days ago and I read that WinXP (and Win2K also) doesn't know how much L2 cache our CPUs have. As a result, Windows doesn't use the CPU as effectively as it possibly could.

From this page:

L2 cache size
Reg Key: HKLM\System\CurrentControlSet\Control\Session Manager\Memory Management\SecondLevelDataCache
Procedure: enter processor's L2 size

I did this on my WinXP SP1/nForce2 Tbred system at home and it didn't break anything. I didn't have time to benchmark it though so I don't know if it helped. But I have some time here at work today, I'll test it on my Win2K/PIII system and post some results.

Has anyone done this tweak? What were your results?

 

[ivan2]

i doubt that knowing how many L2 the processor will have change in performance to the OS. as far as i know the processor cache is totally transparent to the programmer. Knowing how much cache the cpu has might help an complier make more efficient program by changing the resident set of a program, but i dont think it will have an impact on the OS or higher level pre-complied programs. Again im not very good in OS so post this in the OS forum might give you better reply.

 

[Jeff7181]

Microsoft's opinion

Read the text in the grey box at the bottom.

 

[Megatomic]

Thanks Jeff7181! I reverted to my default setting after running the benchmarks available to me. Using Sisoft Sandra 2003 SE I had IDENTICAL scores with the default value and with 256KB entered. It made absolutely no difference to my computer.

Oh well.

 

[Jeff7181]

As stated in that article, when it can't auto detect, the default is 256k, so you'd be fine anyway... the only people who would benefit are people with an L2 cache larger than 256k and a processor that's older than a P2.