Nope, this is not an error, I indeed experienced a loss of FPS that I attributed to SATA performance loss when
disabling Cstates during an overclock, this is why I wrote this and made a research on Cstates. But the graph indeed shows a loss of performance when Cstates
enabled. Two scenarios:
1) As indicated in the paragraph below, there is loss of SATA performance simply by tweaking Cstates out of their default parameters,
or, more plausible,
2) In fact nothing proves that the loss of FPS I've experienced was due to SATA, it was certainly something else and I've looked in the wrong direction when seeking info on Cstates.
But in the end this made me discover a useful piece of info
.
It was a long time ago, now my OC works so I can't tell you why my FPS dropped down at this very moment.
Anyway, so,
Regarding Offset & Cstates:
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1) Here's a copy-paste from
this thread
A few Words about Offset Vcore.
Me and others have seen that when using Offset instead of manually typing in the Vcore, you get a more stable Vcore - Vcore will fluctuate less VS manual Vcore. This again can contribute to a somewhat lower Vcore needed for a certain clock frequency VS manual Vcore setting.
When you put volt values in the Offset field, you add the Vcore you type in there, to the VID of your CPU. However, the VID will vary between each different CPU, and also the speed you run it at.
My 2500K has 1.2410v VID when at 3.3GHz stock. This VID changes to 1.3410 when I overclock it to 4.5GHz. When I type in + 0.020 Volts for Offset, it will then give me 1.3410v + 0.020v = 1.3610v under load. This was tested with LLC at Ultra high. My real Live Prime 95 Blend Vcore varied between 1.360v - 1.376v. And for the most part was about ~1.368v.
If you are stable at full load, like Prime95 while using Offset, but get BSOD's when Idle/light load it is probably because the CPU Vcore ramps down on different load.
This usually happens at higher overclocks when using Offset. For me it works perfectly to use Offset at 4.5GHz with no BSOD's. But if you get problems on higher overclocks, you can try one of two things:
i) Try disabling C3/C6 states. This will hinder the CPU in ramping down the Vcore (as much?) when at idle/light load with Offset Vcore. (Will try this myself. Got a report it helped stability.) Update! I have been using C3/C6 disabled for a long time now. Turns out these can cause idle BSOD's or freezing if they are at AUTO or ENABLED when overclocking. Me and others have confirmed it is best to leave these two Disabled when overclocking.
Beware though, that when disabling both C3 and C6 the Turbo Ratio: By Per Core function in bios will no longer work.
ii) Use manual Vcore setting instead of Offset.
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2) Another copy paste from
this post, quote by by
JuanJose
Quick note regarding options that can affect subsystem performance
It is NOT advised to make adjustments to Cstates as this can considerably affect hard drive throughput performance ( especially SATA6G SSD or Sandforce 2 based SSD ). It is recommended that all CPU power configuration states be left on their default parameters. Overclocking tests have shown internally no increase in multiplier scaling when adjusting these values. * under special cases with high multi capable CPUs and synthetic high load applications ( Linx, Prime, Occt ) it may required C states to be disabled. This has generally only been confirmed for some 51-54 multi capable CPU’s.
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Et voila. (Thanks for the Heads-up Munaim!
)
