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Discussion Starter #1
Hey everyone,

I still have some systems with first generation i7 CPUs and there's something that bothers me for a long time. There's a theory all over the internet about "QPI must be higher than uncore", some people suggest 8:9 ratio for stability and to avoid 1:1 ratio.

Now technically, it does make some sense, so memory and L3 won't choke the entire QPI link. However, personally, I never experienced any issues or bottlenecks running QPI and uncore at the same clocks.

I'd like to get some output on this subject from others.

Thanks!
 

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Iconoclast
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30,653 Posts
No memory traffic passes through QPI on any single socket LGA-1366 part. There is no bottleneck implied by running uncore at or higher than the QPI link.

Many boards/CPUs are not stable beyond that 8:9 ratio, but some certainly are.

My best Bloomfield part on my X58A-UD5R 2.0 ran 24/7 stable at 4.2GHz core, 3.8GHz uncore, and 3.6GHz QPI. Same chip wouldn't even POST with uncore higher than QPI on my ASUS P6TD Deluxe, and I have other CPU samples that wouldn't work correctly with uncore higher than QPI even on the gigabyte board (though the Gigabyte board was almost always able to run closer ratios).
 
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