Squall Leonhart Posted March 25, 2011 Share Posted March 25, 2011 Just realised theres a 4GB/s reduction in the benchmark module with it disabled vs enabled, this is not reproducible in Sandra. i7 920 D0 @ 3.8Ghz / Corsair Dominator 1600 6GB. Quote Link to comment Share on other sites More sharing options...
Fiery Posted March 25, 2011 Share Posted March 25, 2011 Please post a screen shot of the Cache & Memory Benchmark Panel at both settings. If it's possible, please run the Cache & Memory Benchmark 3 times, to see how stable the results are. BTW, Sandra only measures memory copy bandwidth, so the value you could compare in AIDA64 is the Memory Copy benchmark. And the Memory Copy seems to be the least affected by the C-State setting. Quote Link to comment Share on other sites More sharing options...
Squall Leonhart Posted March 25, 2011 Author Share Posted March 25, 2011 im trying to get a friend to replicate my findings, but so far the benchmark cache and memory tool doesn't seem to be affected by it, its only the benchmark module in the aida categories list. Arctucas reproduced otherwise, and my own testing follows his findings (note to self, don't report bugs after a 3 day stint of gaming) It was actually brought to my attention by a post @ http://www.xtremesystems.org/forums/showpost.php?p=4024584&postcount=8 Im not sure whether to conclude this as a bug in AIDA or a side effect of not being able to shut off cores bouncing the benchmark thread about. but yeah, i've sat there hitting refresh trying to get more than 16xxx once and the most i got was close to 17k, this change is a consistent 19xxx. Quote Link to comment Share on other sites More sharing options...
Arctucas Posted March 25, 2011 Share Posted March 25, 2011 This is quite interesting. I ran the Memory and Cache benchmark with CxE on Auto and again with it disabled: CxE Auto CxE disabled Quote Link to comment Share on other sites More sharing options...
Squall Leonhart Posted March 29, 2011 Author Share Posted March 29, 2011 Arctucas, do you see any difference in the CPU tests? my cpuphotoworxx, zlib and aes results have increased as well Quote Link to comment Share on other sites More sharing options...
Arctucas Posted March 31, 2011 Share Posted March 31, 2011 Arctucas, do you see any difference in the CPU tests? my cpuphotoworxx, zlib and aes results have increased as well I see negligible differences in the CPU test, probably normal variation. Quote Link to comment Share on other sites More sharing options...
Squall Leonhart Posted April 1, 2011 Author Share Posted April 1, 2011 or some updates to the tests i guess. Quote Link to comment Share on other sites More sharing options...
Squall Leonhart Posted April 25, 2012 Author Share Posted April 25, 2012 On these cpu's, it appears C3 is required to get the best results in the aida benchmark however C3 and C6 come at the expense higher DPC latency, and i also find windows to be smoother with them off :\ Quote Link to comment Share on other sites More sharing options...
Squall Leonhart Posted May 7, 2012 Author Share Posted May 7, 2012 Fiery, do you have a Intel contact you should talk to about this?, similar behavior is found on Sandy and Ivy Bridge, but not Sandy Bridge E. Quote Link to comment Share on other sites More sharing options...
Fiery Posted May 18, 2012 Share Posted May 18, 2012 Fiery, do you have a Intel contact you should talk to about this?, similar behavior is found on Sandy and Ivy Bridge, but not Sandy Bridge E. Yes, we do. We'll contact them, but first we have to perform quite a few test runs to make sure we can provide exact numbers ("hard facts") in both states, on Sandy Bridge + Ivy Bridge + Sandy Bridge-E systems as well. It will take some time to gather that data, and we'll only be able to start that test session after the next AIDA64 stable update is released (which should be out in less than 2 weeks). So please provide us a bit more time to gather *.* before we can contact Intel Quote Link to comment Share on other sites More sharing options...
Squall Leonhart Posted May 23, 2012 Author Share Posted May 23, 2012 awesome Quote Link to comment Share on other sites More sharing options...
Fiery Posted July 5, 2012 Share Posted July 5, 2012 I think we've figured out what the reason behind the C-State anomaly. Apparently Intel Turbo Boost only considers a core sleeping (inactive) when it enters either the C3 or C6 state: http://download.inte...nots/320354.pdf (Check 3.3 and 3.4 in the PDF) Hence, if you disable C-States (C3 and C6), Turbo Boost will work less efficiently. And that effectively means that single-threaded performance will suffer when you disable C-States. It is reflected by AIDA64 memory benchmarks which are single-threaded benchmarks. It will not be reflected by multi-threaded benchmarks like AIDA64 CPU and FPU benchmarks -- or Sandra memory benchmarks for that matter. BTW, if you check the measured core clock on the Cache & Memory Benchmark Panel, you may see that with C-States enabled your processor will work at a higher core clock level. On our test system (Core i7-2600 + Gigabyte Z68XP-UD3-iSSD) Turbo Boost could push the CPU up to 3.70 GHz during the memory benchmarks when C-States were enabled, but it managed to push the CPU up to only 3.50 GHz with C-States disabled. Quote Link to comment Share on other sites More sharing options...
Squall Leonhart Posted July 6, 2012 Author Share Posted July 6, 2012 It is true that the single core turbo multiplier requires C state tech, but in my case, its not related When a user sets a multiplier under the stock multiplier, the cpu will always run at that multiplier. I found my asus bios tended to jump to 22x single core turbo at times even when i had turbo boost off and the cpu set to 20x, and 4Ghz was needing to much voltage. in my case, my clock rate is attained from 200x19x. 20x is the normal multiplier for this processor, with turbo being 21x(all cores) and 22x(single core). My CPU is always at 3800mhz regardless of c-state tech (with high performance profile set) so the turbo ratio is not applicable here I have heard another theory about this which sounds more likely. Nahalem was designed with a quad channel partition in mind, but the consumer level parts are Tri channel only. When the cpu is completely awake, 2 of the cores fight over dram latching and result in a slightly reduced throughput. When the cores are able to enter the c state, only the currently active cores attempt to latch and higher throughput is obtained. This doesn't explain why SBE throughput is not improved with C State tech however. Quote Link to comment Share on other sites More sharing options...
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