Hokay, this is something that's been bugging me for ages with regards to the Crosshair V and my FX 8120; There's only two active C-states in the whole processor. (As in; two Clock points. AMD Phenom II processors had Five, IIRC) The one which it spends most of the time at is 4.2ghz (At 1.308v), the second is 1.4ghz, which it barely ever idles at, intermediary ones (2.4, 3.0) are configured, just disabled. Anyway, I've been fishing about seeing if there's any way to properly re-enable the missing intermediate c-states, I can do it currently using Turion Power Control, but that isn't an elegant solution, as it requires I define them each boot and Windows seems to misbehave if it suddenly gains three extra C-states without being told first. So far as I can see; it's related to some of the Bios settings, perhaps the fact C1E is enabled, but I can't find any firm documentation about FX series c-states and how on earth they're enabled, some people tell me Application Power Management was the key, others say that it was in the EPU Power Saving function, but they all seem to conflict somewhat. Anyone happen to have any ideas? Edit; Just did a bit of testing, seems that HPC, C1E and EPU are part of the key. I'll do a bit more to nail down exactly which one is at fault. Looks like C1E might be it, though, as it limits it to a Binary State (High Power/Lower Power) rather than the standard 5-level control that this Processor can provide. As for the changes I actually made; I turned HPC off (As it allegedly can force the CPU to lower Vcore under load, WTF.), C1E due to the alleged Binary State, and changed EPU mode from Auto to Maximum Power Saving. Not sure which of those did the trick, or even if it was all three, but it looks like I've got full c-states now, the processor is also clocking on a per-module basis, rather than the entire chip shifting up and down. 2nd Edit: A bit more testing showed that if you have a full set of C-states and Application Power management enabled; the processor will attempt to remain within TDP by clocking down to 2.8ghz under full load. C1E, on the other hand, is the cause of only having two C-States. I'm not sure why this isn't explained in the Motherboard Bios or even anywhere in the Manual, but there it is. Problem Solved.
