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When do I increase CPU voltage?

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XunknownX

Disabled
Joined
Jul 12, 2003
Location
Palmdale, CA
When am I supposed to increase the voltage of the CPU? I have a 2500+ and I had it OC'd to a 3200+, however, things were good until I went to run Unreal Tournament, then it locked up on me. Do I up the voltage? And if so, by how much? I knwo to watch the temps also as increasing the voltage creates more heat. I'll bust the AS5 I have tonight.
 

c627627

c(n*199780) Senior Member
Joined
Feb 18, 2002
Watch your temps as you increase voltage. See if your overclock can pass memtest86 stability test. or

To test the stability of overclocked CPU, download the latest bug fixed version of Prime95:
http://www.mersenne.org/freesoft.htm

Double click on PRIME95.EXE to start the program.

Just Stress Testing (if prompted) > OK >
Options > Torture Test > Blend (if prompted) > OK


The program should not give any errors.
It may be necessary to run the program 12-24 hours to make sure an overclocked system is stable (no program errors displayed).


If you get errors only after several hours, this is a result of slight instability because the system is running with little or no margin. It's stable enough to boot and to be moderately stressed, but as soon as the system is under enough load to go over that critical point, it will freeze. To be 100% stable, Prime95 should run 12-24 hours without any errors.

The point of testing is to see if you get errors or not thus testing the stability. The meaning of errors themselves is not as important.


Running Prime95 Torture Test for 5 to 30 minutes is enough to get a feeling about general stability. If it seems to be stable, increase the FSB (with 0.025V Vcore increase if needed), or increase the multiplier by 0.5.

Reboot and run Prime95 Torture Test for 5 to 30 minutes and repeat this until the Program displays errors.
It's then time to back down and repeat the Torture Test until there are no errors for at least 12 hours.

It's OK to use the computer while Prime95 Torture Test is running in the background.


After finding your stable point you may want to then retest by going to the Advanced section, setting the password to 9876 and then setting Priority to 10. (You won't be able to use your computer while Priority 10 Prime95 Torture Test is running, but it'll confirm your system stability.)

Use 3DMark to test video card stability.
 

johan851

Insatiably Malcontent, Senior Member
Joined
Jul 24, 2002
Location
Seattle, WA
Right, use Prime95 as a benchmark for stability. I only increase the voltage when I need to. Generally, you'll want to try overclocking only one thing at a time - i.e. your FSB while keeping your CPU constant, or your CPU while keeping your FSB constant. This helps you isolate exactly what is causing instability and consequently what might require a little bit of a voltage boost.

If you know your memory is stable at a certain setting, but you're still gettings errors in Prime95, then bring up your voltage in .025v increments (like c627627 said) until you're stable again. Remember to keep your temps below at least 50C on load.
 
OP
XunknownX

XunknownX

Disabled
Joined
Jul 12, 2003
Location
Palmdale, CA
I have a barton 2500+ and it's default 166 FSB. However, I can only get the FSB to 195 and I'm running PC3200.....OCZ....good stuff. So, if the RAM can't run at it's defualt speed, then it has to be the CPU or core volatage I think. Suggestions? Comments?
 

flowrider

Member
Joined
Feb 4, 2003
Location
Aldergroovey, BC
XunknownX said:
I have a barton 2500+ and it's default 166 FSB. However, I can only get the FSB to 195 and I'm running PC3200.....OCZ....good stuff. So, if the RAM can't run at it's defualt speed, then it has to be the CPU or core volatage I think. Suggestions? Comments?

I have the same OCZ ram as you. I can get 200 X 11 stable with Prime 95 running for more than 6+ hours but as soon as I up the FSB beyond 201, Prime fails after about 6 minutes or so. I'm going to try and up the Vdimm. I'm looking at Winbond and I think that it calls the Vdimm, Vcc. It's running at 2.62V. Hmmmm. That doesn't sound too low as it is does it?
 

Mr. Fancypants

Registered
Joined
Dec 10, 2003
XunknownX said:
I have a barton 2500+ and it's default 166 FSB. However, I can only get the FSB to 195 and I'm running PC3200.....OCZ....good stuff. So, if the RAM can't run at it's defualt speed, then it has to be the CPU or core volatage I think. Suggestions? Comments?

Yeah as long as that ram is good and basically running underclocked at default voltage, try upping the vcore voltage a bit. Well thats what I would do he he he.
 
OP
XunknownX

XunknownX

Disabled
Joined
Jul 12, 2003
Location
Palmdale, CA
mobo is spec'd to do 400mhz FSB so something else is holding it back. That's why I asked about upping the core voltage.
 

jonspd

Super Speedy Senior
Joined
Jan 18, 2003
change you timing's for you ram and see what happen's.


max vddim, different ram slot, lower mutilipler if you can,
 

StinkNBreff

Member
Joined
Nov 14, 2003
Last I heard only the Delta- ilsr was guaranteed to run 200 fsb as it is the only one using the Ultra 400 ?? No ??
 

Sentential

Contributing Member
Joined
Sep 16, 2003
Location
Knoxville, TN
Ive got the same problems with my mushkin. Just play with the timings, and it will work out fine. Whenever the CPU becomes unstable on Prime95 its time to give it more juice.


Now...voltage eh? You wanna see High Voltage? Try 1.95volts on a lowly Thermalright SK-7 Without a Vantec Tornado Fan.:eek: *sob* The price I pay to finally reach 2.4Ghz. Just raise the V-core until youre uncomfortable with the temps.

Then burn that sucker in with Prime95 and that will allow you to drop the voltage eventually. (breakin the CPU in)

Once heat becomes a problem you know, that once and for all your monster is complete! It takes awhile to finilize an OCed rig. Hell it took me almost 7months. But the rewards are like no other


EDIT: Are you running a VIA board?(non-Nforce) If you are (like me) you need to do a pinmod to get past 400mgz on the FSB; Since VIA boards cant lock the PCI bus.
 
Last edited:

CCW

Xtreme refugee
Joined
Nov 8, 2003
Location
UK
StinkNBreff said:
Last I heard only the Delta- ilsr was guaranteed to run 200 fsb as it is the only one using the Ultra 400 ?? No ??

200FSB x 2 (DDR) = 400FSB ;)
 

Sentential

Contributing Member
Joined
Sep 16, 2003
Location
Knoxville, TN
AMD chips are cheap so experimnent. Just dont set the voltage ovrer 2.0 without water cooling. 1.9 is my ceiling right now, I refuse to go higher witout extra cooling.