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JPClyde · 17th Apr 2012, 19:52

Are there any downsides to reducing the voltage on a CPU?

I know it reduces temps and could extend the life of the CPU, but how far could you go (for example with my CPU)?

For example: my stock voltage is 1.375v if I reduced the voltage to 1.3v or even down to 1.25v would there be major instabilities?

Pookeyhead · 17th Apr 2012, 22:56

No disadvantage so long as it still tests as stable, so undervolt, test, undervolt, test... until it starts crashing or producing errors, then up it a fraction. Same methodology as over clocking really.

I undervolt AND underclock my server, as it doesn't require CPU grunt at all. It has a decent , proper hardware RAID card to handle parity calculations, so the CPU is essentially doing very little. It's a Celeron E3200 and it's now running at 0.89v at 1GHz.. it runs that cool I could probably just cool it passively.... and uses about 90 watts when being used, and around 40W idle. Probably half that power is the HDDs themselves.

deadsea · 18th Apr 2012, 02:36

That's pretty much the whole point of undervolting. As low as the cpu will go without being unstable and crashing out. Some recommend going down in little steps, others suggest fairly large steps to map out a possible range then the little steps.

However, one thing that i never really managed to figure out. How do you test the stability of the idle states? Just let it be and see if it crashes out?

Pookeyhead · 18th Apr 2012, 06:11

Quote:

Originally Posted by deadsea

However, one thing that i never really managed to figure out. How do you test the stability of the idle states? Just let it be and see if it crashes out?

Pretty much yes. Leave it on overnight for a few nights. If you plan on using S3 make sure you test that too.

JPClyde · 18th Apr 2012, 10:57

Well I've tried 1.25v for my CPU and I haven't had any issues yet that I could see, was playing Skyrim for a few hours with no problems with a reduction in temps by roughly 10c.

Pookeyhead · 21st Apr 2012, 07:31

Test it properly with Intel Burn Test set to Maximum for 10 loops.

JPClyde · 21st Apr 2012, 10:46

It's ok I've gone back to 1.325v

17th Apr 2012, 19:52	#1
JPClyde Multimodder Join Date: Dec 2011 Location: Bradford, UK Posts: 186	Undervolting Are there any downsides to reducing the voltage on a CPU? I know it reduces temps and could extend the life of the CPU, but how far could you go (for example with my CPU)? For example: my stock voltage is 1.375v if I reduced the voltage to 1.3v or even down to 1.25v would there be major instabilities? __________________ Asus Crosshair III Formula / Amd Phenom II x4 965 3.4ghz / 8gb Corsair Memory / EVGA GTX570 HD Superclocked / Sound Blaster X-Fi Titanium Fatal1ty Pro / Tagan Piperock 800w PSU / Samsung SATA 500gb HDD / Samsung SATA SSD 128gb HDD / DVDRW / Cool Master HAF X Case Last edited by JPClyde; 17th Apr 2012 at 20:08.

17th Apr 2012, 22:56	#2
Pookeyhead It's big, and it's clever. Join Date: Jan 2004 Location: Blackpool, UK. Cheesecake! Posts: 10,469	No disadvantage so long as it still tests as stable, so undervolt, test, undervolt, test... until it starts crashing or producing errors, then up it a fraction. Same methodology as over clocking really. I undervolt AND underclock my server, as it doesn't require CPU grunt at all. It has a decent , proper hardware RAID card to handle parity calculations, so the CPU is essentially doing very little. It's a Celeron E3200 and it's now running at 0.89v at 1GHz.. it runs that cool I could probably just cool it passively.... and uses about 90 watts when being used, and around 40W idle. Probably half that power is the HDDs themselves. __________________ MAIN RIG \|Intel i7 3960X @ 4.7GHz ¦¦ Asus Rampage IV Extreme ¦¦ 16Gb Mushkin DDR3 2133 ¦¦ 512GB Samsung 830 SSD ¦¦ 4TB of HDD Storage ¦¦ 4GB EVGA GTX670 Superclocked SLI ¦¦ Corsair 650D ¦¦ Eizo ColorEdge CG303W & Dell 2007FP ¦¦ Logitech Z623 EARTH\| Celeron E3200 ¦¦ Gigabyte G31M-ES2L ¦¦ LSI SAS8704EM2 ¦¦ 3TB RAID5 ¦¦ Headless - VNC administered MOON \| Thecus N3200pro 3TB RAID5

18th Apr 2012, 10:57	#5
JPClyde Multimodder Join Date: Dec 2011 Location: Bradford, UK Posts: 186	Well I've tried 1.25v for my CPU and I haven't had any issues yet that I could see, was playing Skyrim for a few hours with no problems with a reduction in temps by roughly 10c. __________________ Asus Crosshair III Formula / Amd Phenom II x4 965 3.4ghz / 8gb Corsair Memory / EVGA GTX570 HD Superclocked / Sound Blaster X-Fi Titanium Fatal1ty Pro / Tagan Piperock 800w PSU / Samsung SATA 500gb HDD / Samsung SATA SSD 128gb HDD / DVDRW / Cool Master HAF X Case

21st Apr 2012, 07:31	#6
Pookeyhead It's big, and it's clever. Join Date: Jan 2004 Location: Blackpool, UK. Cheesecake! Posts: 10,469	Test it properly with Intel Burn Test set to Maximum for 10 loops. __________________ MAIN RIG \|Intel i7 3960X @ 4.7GHz ¦¦ Asus Rampage IV Extreme ¦¦ 16Gb Mushkin DDR3 2133 ¦¦ 512GB Samsung 830 SSD ¦¦ 4TB of HDD Storage ¦¦ 4GB EVGA GTX670 Superclocked SLI ¦¦ Corsair 650D ¦¦ Eizo ColorEdge CG303W & Dell 2007FP ¦¦ Logitech Z623 EARTH\| Celeron E3200 ¦¦ Gigabyte G31M-ES2L ¦¦ LSI SAS8704EM2 ¦¦ 3TB RAID5 ¦¦ Headless - VNC administered MOON \| Thecus N3200pro 3TB RAID5

21st Apr 2012, 10:46	#7
JPClyde Multimodder Join Date: Dec 2011 Location: Bradford, UK Posts: 186	It's ok I've gone back to 1.325v __________________ Asus Crosshair III Formula / Amd Phenom II x4 965 3.4ghz / 8gb Corsair Memory / EVGA GTX570 HD Superclocked / Sound Blaster X-Fi Titanium Fatal1ty Pro / Tagan Piperock 800w PSU / Samsung SATA 500gb HDD / Samsung SATA SSD 128gb HDD / DVDRW / Cool Master HAF X Case

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18th Apr 2012, 02:36	#3
deadsea Multimodder Join Date: Oct 2009 Posts: 197	That's pretty much the whole point of undervolting. As low as the cpu will go without being unstable and crashing out. Some recommend going down in little steps, others suggest fairly large steps to map out a possible range then the little steps. However, one thing that i never really managed to figure out. How do you test the stability of the idle states? Just let it be and see if it crashes out?