Two ways to skin a cat - OC i7 920

[jackd104]

Goal is to OC my i7920 from 2.66 to 3.33. I found two ways to do this that are very stable for me.

Config 1: BClock 166 * CPU ratio 20 = 3320 GHz cpu clock. I end up with QPI clock of 2988 and mem clock 996.

Config 2: BClock 285 * CPU Ratio 18 = 3330 GHz cpu clock. I end up with QPI clock 3330 and mem clock 1110.

Running CPU voltage 1.275 in both scenarios.

Is one of these configs preferable over the other? Does it matter that I get higher QPI and mem speeds with config 2? This is the only reason I am sticking with this config for now. Thanks for your thoughts.

 

[jackd104]

Correction: on config 2, the BClock is 185, not 285

 

[tweakbz]

When I OCd to 3350, I tried to keep my memory as close to 1600 as possible.

I take it your memory is 1333? If it is, or isnt and it's 1066, stick as close to it's max rated speed as possible. At least that's what I do and have heard; memory will die sooner or more frequently than the cpu.

QPI replaced the traditional FSB, right? If I'm thinking correctly, higher QPI = better.

 

[jackd104]

Thx for the reply. My memory is 1600 MHz, i'll look into upping it.

 

[jackd104]

Ok, with config 2 mentioned above, I can put my DRAM memory speed to 1480 MHz and it runs fine, but CL latency increased from 6 to 9 clocks. I read that latency has more of a performance impact that speed when it comes to memory, so thinking I should keep mem clock to 1110 MHz for CL6? Why does CL change when I change clock speed - are these settings auto generated or can i somehow increase mem clock while keeping latency at 6 clocks? thanks...

 

[tweakbz]

I've not tried changing any memory timings, but perhaps there might be something within the bios for adjusting timings from auto to user-preferred.

I found a stable OC @ 3200 for my i7..still on a zalman hsf, which is working, but I'm gonna get a V8 soon enough.

My multiplier is 20x, bus speed at 160. QPI is 2870 mhz, core @ 3200. Memory is at 798.0Mhz DRAM frequency (1600). My timings for memory according to CPUZ are 9-9-9-24, which is the manufacturer listed.

I don't know much about timings, so I couldn't tell you what kind of performance increase you'll get with a faster timing but slower frequency.

 

[dark_lord69]

Why would you want to skin a cat?

 

[x-nitrous-x]

+1 for skinning cats