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Lower temps by undervolting/underclocking?

A

AP2

[H]ard|Gawd
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I just put together a small ITX system with some spare parts and I'm stuck with a cooling issue.

I'm using a small case enclosure (Wesena ITX chassis) with very limited airflow. I'm running a Intel 3770S (TDP 65watts) with a Gelid Low Profile CPU cooler which is able to cool a cpu with a TDP of 65 Watts. Currently, the cpu temps are 47-51C idling. Would it be possible to underclock/undervolt the cpu to get a cooler temp? If so, what is the best way to do so?

Intel 3770S
Asrock Z77E-ITX
Gelid Slim Silence i-Plus (CC-SSilence-iplus) CPU Cooler
 
You do have EIST enabled right? Seems temps are a bit high. What clock speed is it idling at? My i7-870 idles at 1.2 GHz.
 
Maybe a little. However all S processors are already underclocked / undervolted at the factory so you may not have much room to go.
 
here some info on under voltage or low voltage OC .

http://www.anandtech.com/show/5763/undervolting-and-overclocking-on-ivy-bridge

As other posted if you have all the energy power management options on Speedstep etc .
you should be running low clock (1600? ) along with low core voltages .

My 3570 runs 28-30c at idle/internet usage and vcore is around 0.950v , so there not a lot to lower if you got speedstep working .

I guess your issue is HS and ventilation from your idle temps, that is pretty high .

Edit: checked out that cooler

http://www.gelidsolutions.com/products/index.php?lid=2&cid=12&id=61

they say you need good cooling through case to run i3/ i5 , even though yout TDP is low than normal i7 they still generate higher heat for same clocks .

Maybe you have setting in bios for fan speeds to increase the temp slope that triggers fan ?
 
Last edited:
thanks for all the input. I adjusted the 1 case fan to exhaust and now temps look like 36-47 browsing the web. hopefully it will suffice, as this is pretty much a light duty machine.
 
I wouldn't accept the statement that those CPUs are "already undervolted" out of the factory. They may be assigned a lower default vcore and frequency, but there are always tolerances which are accounted for in any sort of production line.

I'd suggest going to the 'OC Tweaker' section of your BIOS (bit of a misnomer for your situation) and having a play with the voltages. You'll want to use the 'Offset Voltage' mode otherwise you'll lose your p-states (which you want to keep).

Depending on how fussy you are- I'd suggest making an image of your OS partition before you dive in and start undervolting. I guarantee that you'll see at least one BSOD while doing this. The free version of Macrium does a bang-up job if you're looking for a recommendation.

Anyway, settings you'll want to look at are the vcore (CPU Voltage), VTT (optional), VCCSA (optional), CPU PLL Voltage, and CPU LLC (optional). I've also recently stumbled across the concept of undervolting your PLL to obtain lower vcore requirements at a given frequency- mileage may vary- but it definitely works.

I'd start by taking note of your current vcore- then switching to offset mode with a neutral offset (0v) and move in either direction (- or +) in order to match the resultant voltage with your non-offset default vcore. Here's the part where you may want to optimize your LLC so your load voltages are approximately the same as your idle voltage. (i.e. get rid of vdroop as much as possible). This is optional, but you may find that a vcore setting that is stable while idle BSODs on load.

This is the part where you try to reduce those voltages as low as possible while maintaining system stability. Personally I'd start by finding how low your CPU PLL value can go, then move on to lowering your vcore. Best stability test (IMHO) is Prime95 blend- AIDA64 is alright as well. You may want to open your case up while you're doing this- these tests generate a lot more heat compared to a "normal' workload.

Finally, an important stability "test" that's often neglected when undervolting is to just use your system as normal. Load up some music, browse through a couple of webpages. Ideally there would be a program that cycles through p-states and puts a variable load on your CPU- unfortunately I haven't come across anything like that yet.

Hope I haven't been too ranty or incoherent- happy undervolting!
 
johnmaikeru

Thats all good info but confused on one issue, stock defaults seem to be a off-set method .
meaning at idle in speedstep (1600mhz ) you see like 0.940 vcore and under load 1.070 at 3500 . So it already is offset but I agree lowering it can lower temps as these Ivy bridge are real sensitive to voltage .
 
EIST (SpeedStep) reduces your vcore and cpu multiplier depending on load- each vcore/multiplier pair is known as a p-state- this shouldn't be confused with an offset voltage which can either reduce or increase your vcore across all p-states.
 
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