I just don't understand CPU Voltage

[Key West]

I'm new to OC'ing and I've read numerous articles on it so far. Unfortunately all of these articles assume I understand the basic concepts, so it's frustrating.

OC'ing on a basic level is just FSB x multiplier, but where does CPU voltage come into play?

1. What is the difference if my 2.8ghz CPU is overclocked to 3.5 Ghz at 1.45v OR 1.55v? My assumption is that higher voltage = doesn't crash.. meaning if stress testing fails at 1.45v, bump it higher and it can be stable (provided you have adequate cooling). Am I right or way off?

2. Higher voltage = hotter CPU. But that's all there's to it right? If my voltage is something like 1.6v but through cooling it stays under 50c underload, then everything is fine right? Can higher voltage damage your CPU despite being cool?

Let's start from here. Thanks guys (spec in sig)

 

[Rhoxed]

I'm new to OC'ing and I've read numerous articles on it so far. Unfortunately all of these articles assume I understand the basic concepts, so it's frustrating.

OC'ing on a basic level is just FSB x multiplier, but where does CPU voltage come into play?

1. What is the difference if my 2.8ghz CPU is overclocked to 3.5 Ghz at 1.45v OR 1.55v? My assumption is that higher voltage = doesn't crash.. meaning if stress testing fails at 1.45v, bump it higher and it can be stable (provided you have adequate cooling). Am I right or way off?

2. Higher voltage = hotter CPU. But that's all there's to it right? If my voltage is something like 1.6v but through cooling it stays under 50c underload, then everything is fine right? Can higher voltage damage your CPU despite being cool?

Let's start from here. Thanks guys (spec in sig)

You have the basics it seems, yes more voltage will be needed for an unstable overclock, but every chip has a "wall" where more volts wont help, only sub-zero cooling will.

High voltage can damage your CPU, no matter what the temps are. Its not reccomended to go past 1.5-1.55 on an AMD cpu on air, 1.55 is even pushing it for water cooling. (as a quick reference i run my 720BE unlocked @ 3.7 1.45V for 24/7 use and 3.9ghz 1.52V for benchmarking) temps never go over 55C (anything higher then 60 = back off the OC/Volts)

 

[Hyperlite]

#1 is right on. You always want to shoot for the lowest voltage you can to remain stable. OCing is a balance between voltage and frequency. HOWEVER, there is more to voltage input than temps. Even if temps are kept in check, excess voltage over time can damage a processor. As the previous poster said, AMD quads and X3's should stay below 1.5v, but you'll definitely need an aftermarket cooler to run it there.

 

[veri745]

High voltage can damage your CPU, no matter what the temps are. Its not reccomended to go past 1.5-1.55 on an AMD cpu on air, 1.55 is even pushing it for water cooling.

High Voltage can damage your CPU regardless if temperature too. 1.55V+ on an AMD CPU may be OK for suicide OCing runs on the short term, but that kind of voltage WILL damage the CPU over time.

I wouldn't suggest going over 1.5V for normal use.

As far as why CPU voltage matters: More voltage between the "on" voltage and the "off" voltage on a transistor allows greater switching frequencies because it provides a more definitive "on"/"off" output.

 

[MagnusTheBrewer]

You have the basics it seems yes, more voltage will be needed for a stable overclock. Every chip has a "wall" where more volts won't help, only sub-zero cooling will.

Fixed that for ya.

 

[Key West]

You have the basics it seems, yes more voltage will be needed for an unstable overclock, but every chip has a "wall" where more volts wont help, only sub-zero cooling will.

High voltage can damage your CPU, no matter what the temps are. Its not reccomended to go past 1.5-1.55 on an AMD cpu on air, 1.55 is even pushing it for water cooling. (as a quick reference i run my 720BE unlocked @ 3.7 1.45V for 24/7 use and 3.9ghz 1.52V for benchmarking) temps never go over 55C (anything higher then 60 = back off the OC/Volts)

Hmm, good thing you and I have same CPU + similar setup. My prime95 crashes at 3.6ghz (200 x 18) with 1.5V, why can't mine OC similar to yours? What is your setting for 3.7Ghz, diff FSB0?

My temps are fine at capping at 51C

 

[veri745]

Hmm, good thing you and I have same CPU + similar setup. My prime95 crashes at 3.6ghz (200 x 18) with 1.5V, why can't mine OC similar to yours? What is your setting for 3.7Ghz, diff FSB0?

My temps are fine at capping at 51C

Not all chips are created equal. Some will overclock much better than others. Some will overclock the same but with less voltage. Some need more voltage but will overclock a lot more.

All you can do is find the limits of your own chip and get the most you can out of it.

 

[Athadeus]

It may well be related to your memory timings and frequencies Key. You could either try increasing your memory voltage, NB/MCH voltage, or increasing your memory timings. Just make sure that you stay in spec for whatever you do.

 

[soccerballtux]

Hmm, good thing you and I have same CPU + similar setup. My prime95 crashes at 3.6ghz (200 x 18) with 1.5V, why can't mine OC similar to yours? What is your setting for 3.7Ghz, diff FSB0?

My temps are fine at capping at 51C

try 3.5ghz, I can't hit 3.6ghz no matter the voltage (tried 1.55v) but I can do 3.5 all day. Also don't forget about overclocking the L3 cache on these (CPU-NB in your BIOS), I run mine at 2.6ghz and it needs +0.2v to do so. Improves performance as well, usually 7% up to 10-12%.