955 won't throttle down at idle when overclocked beyond a certain amount

[tomalok]

I overclocked my cpu to 3.7 ghz (set the multiplier to 18.5, didn't touch the voltage) and it idles at 803 mhz and 1.025v. Under load, it goes up to 3700mhz and voltage goes up to 1.4v. It's 30 degrees C at idle and goes up to 45 under load, so there's a potential for a much higher overclock.

But when I up the multiplier to 19 (still don't touch the voltage), it's now always at 3800mhz even when idle, and the voltage stays at 1.4v. Nothing else has changed in my bios settings other than the multiplier being 19 instead of 18.5, the AMD Cool and Quiet setting has remained on "auto".

I'd like to keep my idle power consumption low, even if it means a lower overclock, so I'm keeping it at 3.7 ghz for now. But what is the reason that it won't throttle down at 3.8 or higher? Is there some setting I'm missing somewhere?

My CPU is the 955BE and my motherboard is the GA-870A-USB3 Rev 3.0.

[absic]

Hi there,

Somewhere on the forum, there is a similar post regarding this issue but I can't find it at the moment. And sadly, it was made quite sometime ago so I can't clearly remember what the outcome was.

In the back of my mind, I seem to recall that this happens when you go to 3.8GHz or above and there was no proper explanation. I will keep searching the forum to see if I can locate the original post for you.

[Dark Mantis]

Yes I remember the same thread absic. Had a feeling it was to do with making sure that the Turbo was off above 3.7Ghz but I must admit I can't be sure.

[absic]

OK, my memory isn't as bad as I thought and it seems as if, when you unlock the CPU multiplier, the Cool N Quiet option becomes disabled.

Here are a couple of relevant posts I have tracked down which seem to confirm this:

http://forum.giga-byte.co.uk/index.php/topic,632.0.html

http://forum.giga-byte.co.uk/index.php/topic,728.0.html

[Dark Mantis]

The search engine on the forum is a bit lacking to be honest. Trying to find certain things can be a nightmare.

[tomalok]

Thanks for finding those threads absic. But I don't think I have the same problem as described there, as they claim that CnQ doesn't work at all when overclocked. In my case CnQ works fine when overclocked up to 3.7 ghz, it's only when I overclock to 3.8 or higher that it suddenly stops working.

Is this a bug in my Gigabyte motherboard? Or is it necessary behavior for some reason? In any case it's not a huge problem for me since at 3.7 ghz my cpu is more than powerful for my needs, I was just curious.

[absic]

Hi Again,

it seems to stop working once you go above 3.7Ghz and I have noticed this on my own system when I tested it out earlier today, after tracking down those threads and I'm running a 1090T on the GA-990FXA-UD5. C'n'Q works fine up to 3.7GHz once I take it over that it stops working and the only thing I can think of is that it is a safety thing to protect the CPU in some way.

Also, it is worth bearing in mind that, usually when overclocking the CPU you would disable these features anyway which is probably why it isn't noticed very often by other users.

[sixor]

my giga mobo disables cnq when OC, yeah it sucks, i want to decide, not the stupid mobo

the solution is learn to use

PhenomMsrTweaker

you install it, then use it, it is very easy, don´t touch numbers, just enable things and you will get cnq back, and my oc is stable at 3917 with cnq on, thanks gigabye for disabling cnq for nothing