Uncore:QPI ratio?

damir_d

Distinguished
Jul 18, 2009
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I've been looking at all kinds of guides.... and some are saying that having a 8:9 uncore to QPI ratio is important

My Current set up is:

i7 920 D0 @ 3.8GHZ (181 x 21 CPU) @ 1.20625 Vcore
CBLK @ 181
DRAM @ 1810MHZ 8-8-8-24 (2:10) @ 1.64V
uncore @ 3620MHZ (CBLK x 20)
QPI @ 3258 ((CBLK x 36)/2)
QPI/DRAM @ 1.375V

Prime95 Small FTTs with RealTemp

Core Loads @ 64C Max @ Ambient 25-27C

Now I am running into this problem, I am unable to get my System to post at all when I select QPI at a Ratio of ~ 9 to the Uncores of 8,
if I was to follow the rule to achieve stability.

How Important is it, to keep the Uncore to QPI ratio of ~ 8:9?
Is there any evidence of reduced system performance of running Uncore higher than QPI?

I have had this setup runningfor the past 2 days, and have not encountered 1 problem so far. It passed numerous intel burn test of
20 passes @ 1024MB and 8 threads.

Reason why I bench with intel burn test, it seems to find instabilities in 4 passes or less (@1024MB RAM usage, each pass is at about 17-18seconds),
where as prime95 would never show one, even after of 13+ hour runs, both at same system settings.
 

overshocked

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Feb 14, 2009
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Im assuming you read my guide on toms hardware?

The QPI step is not crucial. If you dont do it then it may require a little more QPI or uncore voltage. But that is not a problem.

I can achieve 4.53 without adjusting the QPI ratio at all.