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Power (Supply) related question...

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pkipper

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Joined
Feb 6, 2002
Location
Melbourne, Victoria, Australia
Power (Supply)/Overclocking question...

Hi guys,

A question related to power supply and the voltages...

For a typical power supply, it mainly consists of the +3.3V, +5V, +12V, +5VSB, -5V, -12V and so on. I don't know much about how the each trail is distributed but from tracing the wires, I guess most of the +3.3V goes to powering the motherboard, the +5V and +12V power stuff like fans, hdds, cd-roms, motherboard...etc.

My question is, if I increase the vcore, ram or the agp voltage, from which trail (+3.3V, +5V or +12V) does the extra voltage use up the most?

Also, if I need to overclock, which trail do I need to make sure it doesn't drop in order to keep stability?

Many thanks.
 
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I believe it's the 3.3 volt that powers ram and agp as well as much of the processor.

I've been shopping for motherboards this past week, and some actually say 3.3v agp or 3.3v memory in the spec rundown.

Since an overclock draws from both the 5 and 3.3 volt lines, you should watch both for stability issues, and use a psu that has plenty of wattage on these legs.
 
Hi Diggrr,

Thank you for the info. So just exactly how low are the +3.3V and +5V allowed to reach before they make the system unstable?

So the +12V doesn't matter too much?

I just been having an extremely hard time getting my system stable. Sometimes I cannot even get into Windows at 145 fsb, sometimes I can get into Windows, run 3DMark for 30 minutes before crashing at 150 fsb. I brought a new ps but still doens't help, so annoyed :( :( :(
 
Let us know what a couple more of your specs are and we can probably help out a little...

What chipset does your Mobo use?
How is the Chipset Cooled?
What is your CPU temp?
Is the Multiplier unlocked?
How is your Graphics card cooled?

I put a new cooler on my Via kt266A chipset, and I was able to up the FSB an extra 5 Mhz!
 
Hi Darrenct,

My mobo is KT266A chipset.

The CPU temp is 29c idle and 38c full load (using WPCREDIT tweak).

The chipset is not cooled, but I have a side intake that blows straight on top of the AGP and the mobo itself. Also another custom fan that is blowing at the back of the back approx where the CPU is located.

The Multiplier is not unlocked. I am scared of damaging and I don't have the spare cash :(

Graphics card only has the heatsink, only cooled from the side intake fan.

Ram voltage right now is upped at 2.6V, Vcore is at 1.80V.

I cannot give you an accurate reading from the voltages (+5, +3.3, +12...etc) cos MBM 5 doesn't work so well with my mobo and the readings from that isn't very accurate. I have attached with what I thought it was the most accurate readings from MBM 5.

The other info you can get them from the sig below.

I am not sure why but my system seems to overclock better at night (when it's cooler). But I don't really know since the system is already pretty cool. Right now I am on 147 fsb and played 2 hours of Counter Strike without a single crash. Just three hours ago I had to lower my fsb to 140 because the game kept on crashing at 145. Strange huh?

I also brought a new ps hoping to solve the problem, but I guess not. I am so disappointed.

If cooling is really the problem (like what you said, you got a new fan+hs and you could get that little extra mhz), then I would get a new fan+hs. However I really hate to spend more then find out at the end that that the extra addition doesn't help.

Thank you for your help :)

PS. The readings in the attached file are recorded while playing Counter Strike early morning. FSB at 147. It begun when I just got into windows, and into the game, then exit the game. The temp readings are accurate (AGP and CPU), but voltages at not.
 
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Just 10 minutes after I posted here, the computer finally crashed after running SETI@Home for 5 minutes. After that it couldn't get back into Windows and I had to set my fsb back to 145. Doesn't matter what I do, up the voltage, up the vcore, I just cannot make back at 147.

The new readings from MBM 5 is attached. I hope the experts in this forum can help me out. Many thanks.
 
Your CPU temp is great. So I wouldn't worry about that. I would recommend getting a cooler for your Chipset though. Although it won't overheat, it will run at higher FSB when it is colder.

Like I said, I went from 145 to 150 on the FSB just by putting a crystal orb on it. If a chipset cooler doesn't help, you may have to get a new HSF... But I think that cooling your chipset will make a big difference.
 
Hi Darrenct,

I see. I will give it a try. Even if it doesn't work, an extra cooling device wouldn't do any harm anyway :)

Just as a matter of interest, do you have links that points to the intruction on how to install it to a mobo or video card? Just incase it doesn't come with instructions since I have never had a chipset cooler before :).

Thank you,

Hi flounder43,

I will make a note on my +5V rail. Right now it's 5.05V and I think that's pretty accurate, but computer still crashes but yet the +5V does not drop. SOOOOO STRANGE!
 
Run mbm at the same time as a work load. Check the voltages very carefully. Set mbm to read out every sec while doing this. Your true voltage (the one that matters to you) is what it is under load. I would have sworn I checked sisoft today and the agp was 5v. Could be wrong, need to check again. While doing the load check watch both the 5v/12v and the 3.3v. It does not take much on the 3.3v to stop the works. I presently have my 3.3v set at 3.49 idle and the 5v at 4.97 under load.
 
Hi Darrenct,

Hehe, that does sound easy. I just hope I have enough room for a large cooler like the Crystal Orb. Just incase they are too big (which I am trying to find out now), are there any other coolers you can suggest me? Although I really like the stylish look of the orbs :)

Hi Silver,

Your 3.3V is at 3.49? That is impressive! How is that possible? Did you mod your power supply?

Actually, I have tried to monitor the voltages second by second, but still cannot work out why. It would only vary by 0.01V under full load and that's all. When the computer crashes, it would still show the same thing the very last second before the computer crashes, and never a sign of a voltage drop. So confused. Which is why sometimes I can run everything fine at 147 fsb for hours, but sometimes cannot even get into Windows at 145 fsb. I did hit 150 fsb a few times, but crashes when using SETI@HOME for a few minutes. :(

Hence I can only try what Darrenct suggested, cool the chipset. I would be very suprised if that works, but I still like to give it a shot.

Thank you all for the feedbacks. :)
 
I believe your CPU is run off of the 5v line. More definitively I know that the AGP cards are run off of the 5v line and not the 3.3v as posted earlier. I believe Mr. Hoot has posted with instructions on how to improve voltages when they are affected by things like bad connections and thin on-mobo conductors.

Some time ago there was a post on how to jumper the 5v directly to the AGP socket.
 
inertia said:
I believe your CPU is run off of the 5v line. More definitively I know that the AGP cards are run off of the 5v line and not the 3.3v as posted earlier. I believe Mr. Hoot has posted with instructions on how to improve voltages when they are affected by things like bad connections and thin on-mobo conductors.

Some time ago there was a post on how to jumper the 5v directly to the AGP socket.

Have to go look for that article as it may help mine out.
 
The orbs are a little bulky, here's a vantec chipset cooler that isn't round:
Vantec Chipset Cooler

It looks like this one may use the same heatsink as your mobo, just with a fan. If it is the same, you won't have to glue the new one on, you should be able to clip it in. Just make sure you put some thermal paste in there..
 
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