Uncore overclocking past 2X RAM

[Rubycon]

This pushes the memory bandwidth to the ceiling and latency a few ns lower. It also gets unstable if you go too far.

Outside of that is there any advantage to the higher bandwidth? 25GB/S write vs. 22GB/S write in Everest. Latency went from 47ns to 43ns. 12GB Corsair Dominator 1866 at 1650 8-8-8-24-1T timings.

 

[dmens]

didn't improve my x264 runs when i kicked the uncore up from 2.4ghz to 3.2ghz. but it was still rock steady at 3.2ghz so i left it.

what some mobos call the QPI voltage is actually the entire uncore voltage, so raise that if there is instability.

 

[alyarb]

Originally posted by: dmens

what some mobos call the QPI voltage is actually the entire uncore voltage

damn, i did not know that.

 

[imported_Shaq]

Northbridge(IOH) is also involved in uncore. Look in CPU-Z it shows the Uncore frequency as the Northbridge frequency. Once you get over about 3.2 the IOH core voltage needs to be adjusted upward. With 2000 memory frequency(4000 uncore) a lot of people I have seen need to raise IOH up to at least 1.24v from 1.1v default. QPI needs to be raised also but that is because the QPI link is higher than default- 7200+ usually- 8000 is the general limit and many chips can't go that far. QPI is also for the IMC and the voltage will need to be raised the more memory you have/tighter timings. My CPU has a weak QPI and can't go over about 7200 even if I raise QPI to 1.5v+. If you have a 965/975 the BCLK can be much lower, and IOH and QPI, since the multi can be raised instead. That is the only reason to buy those chips other than bragging rights/e-peen/non-OC'er.

And for the OP's question I believe it only shows a benefit in synthetic benchmarks and it might lower superPI time. The i7 needs 6+ cores to benefit much from triple channel memory according to Intel so there won't be much benefit in everyday apps.

 

[Shmee]

Actually, I find that my system seems a bit more stable with slightly higher than 2x+1 uncore. I use 6x Ram, and I believe I am at 14x or 15x uncore.