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 Post subject: Please help me undervolt
PostPosted: Tue Feb 12, 2008 9:40 pm 
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I've never overclocked or underclocked or undervolted anything before so I'm clueless. But my PC in my AV cabinet keeps overheating. Please help!

1. I'd like to undervolt my Intel Core 2 Duo, here are the specs:
Mobo: P4M890T-M2 v1.0B
CPU Speed: 1.86 GHz
Bus: 1066
L2 Cache: 2 MB
L2 Cache Speed: 1.86 GHz
Package type: LGA775
Thermal Spec: 0.85V - 1.5V

2. I'd also like to cut the heat on my video card, an 8600 GT.

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PostPosted: Wed Feb 13, 2008 6:53 am 
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What is the airflow like in your AV cabinet. No undervolting will keep a completely enclosed system from overheating with use. If you have a closed-back cabinet you may need to do some creative cutting and make some holes for exhaust fan(s) (and maybe an intake fan if there is a front door on it as well) fans to be installed. There are a few posts around here where people have done the same thing using 12v fans and power adapters or using 120V (which I don't recommend).

However, if you do still wish to undervolt, make sure the system is stable at stock levels first. Most of this stuff will need to be done in the bios, and will require considerable Trial and Error on your part.

First thing is to read your mobo manual and find out how to enter the BIOS and lower your CPU voltage to the lowest point at which it's stable.

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PostPosted: Wed Feb 13, 2008 7:08 am 
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Thanks! My cabinet already has decent ventilation with some 120mm fans, but it's big and there's a lot of stuff in it so I guess it still isn't enough. My computer overheats after 4-5 hours.

Here are some specific questions:

1. For my CPU, do I just have to lower the vcore in my BIOS, or will I have to lower the clock speed as well?

2. My video card is super-hot. How can I undervolt that too?

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 Post subject:
PostPosted: Wed Feb 13, 2008 8:03 am 
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Quote:
2. My video card is super-hot.


how hot is superhot. many VGA cards are designed to operate at up to 85/90C without artifacts.

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 Post subject:
PostPosted: Wed Feb 13, 2008 8:16 am 
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Phoner wrote:
1. For my CPU, do I just have to lower the vcore in my BIOS, or will I have to lower the clock speed as well?

2. My video card is super-hot. How can I undervolt that too?


1. Lowing your clockspeed allows you to lower your voltage even further, higher clocks usually require higher voltage. I loved the days of unlocked multipliers, since you can change CPU speed independent of FSB, but unless you get a "Black Edition" AMD processor, that's not gonna happen.

2. Ditto jaganath on the video card. But usually GPUs tend to be a little less workable with voltages. The only way I know is to use NiBitTor to change the default clock and voltage in the video BIOS.

A better description of the cabinet (maybe some pics) would help us to help you. You say it has some 120mm fans for venting, but is the front open or closed (if it's closed, where is the fresh air going to come in)? Where are the fans located? If you take your PC out of the cabinet and it works fine, but you put in in the cabinet and it crashes due to heat errors; the problem is your cabinet and its ventilation, not the PC.

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 Post subject:
PostPosted: Tue Feb 19, 2008 6:31 pm 
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I followed this article as a tutorial:
http://www.nordichardware.com/Articles/?skrivelse=465

Using a utility such as RightMark is a good solution for someone not used to playing in the BIOS because...well...you don't have to play in the BIOS. The disadvantage is that the software does have to be running in order to have an effect, and I suppose it would be less robust than changing the voltage at the mobo itself. But hey, it's easy. (And it's the only solution for people like me with OEM motherboards that don't support this kind of setting.)

If you do want to give it a shot, you must...and I can't stress this enough...TAKE_YOUR_TIME! If you aren't spending several hours taking the voltage down step by step, you probably aren't doing it properly. It's imperative that you test for stability as you go along lest you go too far and wind up with an unstable machine. Also, be forewarned that taking it down all the way to the minimum does, by definition, mean that you will probably take it one step too far and crash. A big deal? Wasn't for me, but don't try to write your novel at the same time and don't have autosave turned on.

That said, the others are 100% right about ventilation. Even a minimal power source will result in heat buildup in a confined space. That's just thermodynamics.


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 Post subject:
PostPosted: Tue Feb 19, 2008 7:18 pm 
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measure the ambient temp in the cabinet after 5 hours first, so you know what your working with.


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