i7 720qm vs 930 cache bandwidth in memtest

[Athadeus]

Hey guys,

I just got a new 1366 computer setup last night, though I have a lot of work left to do on it. I have hardly changed any settings from default so far except forcing the DRAM bus voltage down and manually setting the DRAM frequency and basic timings.

However, I noticed quickly that the cache bandwidths seemed significantly lower than on my Asus G73Jh as reported by Memtest86+. I was using version 4.00 at first, but I updated to 4.10 to make sure there wasn't a bug that had been fixed (with no change in the results). I downloaded the Everest ultimate trial, but I couldn't find the right test, and I figure the trial might not show the numbers I want anyways.

Asus G73Jh
1.6ghz i7 720qm
4x2gb DDR3-1333 Kingston 9-9-9-24
32KB L1 cache @ 106,402 MB/s
256KB L2 cache @ 39,901 MB/s
6MB L3 cache @ 26,164 MB/s
Memory @ 13,082 MB/s

Intel Core i7 930 2.8ghz
Asus Ramage III Gene
3x2gb DDR3-1600 G.Skill 9-9-9-24
32KB L1 cache @ 54,972 MB/s
256KB L2 cache @ 32,224 MB/s
8MB L3 cache @ 25,720 MB/s
Memory @ 13,743 MB/s

How do these compare to some of your statistics? I know that L1 & L2 cache are tied to the CPU frequency, but stock or overclocked results are fine.

If these results are not normal, what (default) settings might be wrong? If they are to be expected, why is it?

Thanks for any insight!

 

[Athadeus]

Well, I suspected that the i7 720qm was based on lynnfield, which I have confirmed. I guess there is no limitation on cache bandwidth caused by heat or power since the 45w processor seems to dominate the 130w one in those few narrow statistics.

However, I am still curious if the cache bandwidth is on par with some of your stock speed bloomfield systems. I want to run more stability tests and let the AS5 cure more before I overclock it.

 

[IntelUser2000]

Are you sure those two results are from the same benchmark program? They should be getting identical results per MHz for the L1 and L2 caches*. I'm not sure how Turbo modes work with the application you are testing and 1 and 2 core modes for the i7 720QM are much higher than the base frequency.

*Applies to Bloomfield/Lynnfield/Clarksfield/Clarkdale/Arrandale/Gulftown/Xeon 5500/Xeon 5600, name any Nehalem and Westmere cores and it'll be true.