Overclocking Overclocking - Advice on how to reduce temps

Perfect As I've said, 70 is my limit, seeing as your CPU will never reach 100% in any task apart from benchmarking and stress testing...

 

Thats was gonna be my next question.... will i ever stress the CPU & GPU this much gaming?

I turned the fans back up, and drop the voltage to 1.187 in the bios..... But CPUz is saying that is 1.072v

Noticed an option for Execute disable bit - enabled. But i left this on as it sounded important!

Temps are looking the same really. 60/61c under load

 

Very true, Furmark & Prime running together will heat it up more than any game you are playing.

I guess I am just a little more conservative than you Pete (or I have less money).

bdigital: does your CPU temp change if you switch the rear fan from low to high then back again? You may benefit by having the a Gentle Typhoon on the rear instead of the TriCool, it will shift more air. It sounds like you have enough intake.

I didn't notice any temp difference in switching 2 x Gentle Typhoons with 2 x Silent Eagles in the front of my Antec 300, only noise. The top doesn't make a huge difference, the rear does though as it is drawing the hot air away from the CPU cooler, assisted by the CPU fan blowing towards it. Worth a try if you want to fiddle.

 

Disable Execute Disable Bit, it will be more stable under an overclock usually.

There will always be a difference between the BIOS and CPU-Z, that is just the way things are. You could also be suffering from VDroop under load where inefficient power circuitry to the CPU sucks voltage away from the vcore under load. Google it if you want to learn more arcane terminology that isn't relevant with the more modern CPU's.

 

Disable Execute Disable Bit is build in anti-virus I though, as it stops them using parts of the CPU cache...

 

vdroop is there by design.. when the cpu loads there is a momentary spike in voltage.. vdroop guarantees that spike won't exceed the voltage you set in the bios

intel chips seem to be able to take the spike just fine though without electromigration issues.. so a lot of people used to disable it by penciling in the resistor- and manufacturers started including the option in the bios

intel spec.. that e8600 should be kept under 72C

 

When I overclock my CPUs, I'm happy with temps up to 80C while Prime95, because no game will push a CPU as hard as that.

 

In your Antec 300, the bottom front fan will be blowing air towards the PSU and GPU. If you have a PSU wth an intake on the inside of the case facing up, all that cool air will be sucked straight out via the PSU fan. The upper front fan is the one which gets the most air to the CPU cooler. A smaller heatsink such as an Arctic Freezer may not benefit from the directed airflow as much as a huge heatsink like a Titan Fenrir.

With the CPU cooler fan blowing towards the rear exhaust fan, you kind of have a push/pull effect.

More or less...

Quote: "Execute Disable Bit allows the processor to classify areas in memory by where application code can execute and where it cannot. When a malicious worm attempts to insert code in the buffer, the processor disables code execution, preventing damage and worm propagation."

Source: http://www.intel.com/technology/xdbit/index.htm

In every overclocking guide I have seen the recommendation is to turn it off. I think this is to ensure stability with an overclock but if it is stable with it on...meh.

I stand corrected. Does vdroop still occur in the newer CPU's with an on chip memory controller or is it just managed within the on chip memory controller?

Afaik, Intel don't publish the actual temperature that a chip should run at, only the TJMax figure?

A couple of very interesting threads about CPU temperatures, TJMax and temperature monitoring software...

http://www.overclock.net/intel-cpus/375827-attention-all-intels-official-tjmax-temps.html

http://www.overclock.net/intel-cpus/476469-truth-about-temperatures-voltages.html

 

Ive dropped the vcore down to 1.1625 now, CPUz is showing this as 1.056v. Im not 100% sure that I am using the correct option for changing the vcore, its an option in the ‘Overvolting’ menu…

I havnt had time to test much since lowering the voltage again, but 15mins of Prime95 & Furmark and CPU didn’t go above 56c.

I also found that nvidia option called ‘GPU Ex’ which is enabled, maybe this is something to do with Physx? Il investigate!

 

Dropped the vcore down to 1.10000v now. CPUz is showing 0.976 V.

Its maxing out at 50c with Prime95 + Furmark running (40mins and going)

EDIT: 1 core failed. Bumped voltage back up 2 notched now.... il do it until prime keeps going for a decent amount of time

 

Are you taking the voltage reading on CPU-Z on idle or under load because that difference would be about right between idle and the CPU going flat out. I know for a fact that mine will rise and fall by about 0.25 depending on the load.

 

Right.... Under load. CPUz is now showing as 0.992v.

This is after i bumped the vcore back up a little.

So far (10mins) Prime95 is running ok, along with Furmark im maxing out at 54c. But that wiull prolly rise a few over time.

Just played approx 2 hours of Fallout NV on high settings and highest temp was 48c.

Seems happy, could even oc a little more maybe, but i dont neeeeed to lol

 

OC until it gets unstable on those voltages and then back it off a bit and you have a nice middle ground between a bit of extra speed and keeping the temps under control...job done.

 

well the temperature can vary.. like the 65nm conroes (E6600) was under 60C and the shrink allowed them to run hotter according to intel.. I usually take the tjmax on the arc as a good limit on the cores

I figure the intel engineers would know better than anybody about when electromigration becomes an issue.. same with the voltage- if your disabling vdroop (load line calibration on the new gigabyte boards), you have to account for that spike

so you'd probably want to run lower than the voltage posted in the arc for your chip to be safe if your on air.. water is another story- the temps are low enough that voltage can go higher safely.. those paths don't degrade and blow apart if kept cool enough with ln2 being an extreme example, or phase cooling

 

Yeah, I think I got my preference for 60C from when I was clocking my E6600 (65nm) and just kept that...I have more leeway with my E8600. Saying that, 3.8GHz on air whilst keeping the chip around 60C is good. Iirc my E8600 is @ 1.28v idle in CPU-Z.

 

I tried upping the overclock a little last night, and it didnt go too well! I got it to 4GHz ok, but it needed more voltage to stay stable, and it was nearly 2am so i gave up tinkering.

When i reverted back to my original settings and ran Prime95 + Furmark it wasnt stable, and one of the cores kept shutting down.. doh! Obviously it didnt like me trying to squeeze more out of it.

I stuck with 3.8GHz an added a bit more voltage this morning, and so far... 3 hours 15mins in, and the highest temp recorded is 59c with both Prime95 + Furmark running concurrently. Furmark is showing highest GPU temp as 75c, with an average of 78fps.

CPUz is showing 1.008v at full load. So hopefully i have found the sweet spot again. Bearing in mind that the ambient temp is fairly low this time of year, i might need to adjust things when things warm up a little.

My next steps are to play with the fans as Fingers suggest earlier....To try and work out how much effect the rear exhuast is having on CPU cooling, and to perhaps swap the lower front Sycthe Gentle Typhoon with the Antec stock one.