How can you tell if a PSU is a limiting factor in OC'ing?

A few months ago I bought a Sparkle ATX-300GT 300W PSU (PDF specs) for less than $20. It's been good to me so far, but I'm wondering if I'm stressing it too much with my system and if it's somehow limiting my overclock. This is what I'm running now:

Abit NF7-S v2.0 (I'm planning on doing the VDD and Vdimm mods soon)
2100+ @ 2365mhz ~1.95v
512MB Corsair ~2.9v
Radeon 9800
30MB Maxtor HDD
40MB Maxtor HDD
Liteon CD-RW/DVD
2x80mm fans
120mm fan
12" CCFL
6" CCFL


The reason I ask this question is because my rails are doing pretty darn well. Under load I get:

5.09-5.11v
11.95-12.01v
(checked with a multimeter)


So are low rails the only way to tell if you're stressing a PSU? Would a bigger PSU allow me to overclock more, espically since I'm planning on more volt mods?

Sparkle PSU's are known for being conservatively rated, and generally good performers.

AFAIK, as long as your voltage is at the upper limit and steady, the PSU is fine.

I've had a PSU that was limiting my overclock, and there was no doubt about it. My generic 400 watt held up fine with a KT7A SDRAM motherboard, and a GF2 Ti. But with an 8K3A, DDR, and a GF4 Ti4200, it began to wilt. I could still overclock my 1600, but after I would turn the computer on, the voltage readings would steadily drop in MBM, until it would finally reboot. I had to back off to stock to avoid damaging anything while I waited for my new PSU to arrive.

I think you're fine with those voltage readings.

how would one check if they didnt have a multimeter? (or might be able to get one but wouldnt know how to use)

A few months ago I bought a Sparkle ATX-300GT 300W PSU (PDF specs) for less than $20. It's been good to me so far, but I'm wondering if I'm stressing it too much with my system and if it's somehow limiting my overclock. This is what I'm running now:

Abit NF7-S v2.0 (I'm planning on doing the VDD and Vdimm mods soon)
2100+ @ 2365mhz ~1.95v
512MB Corsair ~2.9v
Radeon 9800
30MB Maxtor HDD
40MB Maxtor HDD
Liteon CD-RW/DVD
2x80mm fans
120mm fan
12" CCFL
6" CCFL


The reason I ask this question is because my rails are doing pretty darn well. Under load I get:

5.09-5.11v
11.95-12.01v
(checked with a multimeter)


So are low rails the only way to tell if you're stressing a PSU? Would a bigger PSU allow me to overclock more, espically since I'm planning on more volt mods?

Click to expand...

your chip already seems to be at the upper limits of likely speeds...2.4ghz! with already very high voltage...

if i were you, try to find a more powerful supply to test the system with and see if it adds to the overclock...but i doubt it...

that said, you are probably overloading that psu...particularly if your mobo supplies the cpu with power through the 12v line...

if you must upgrade, then get the fortron 530 or antec tp 480, 550...since the fortron 350 would be an upgrade...but not a big enough upgrade for the price

Software such as Motherboard Monitor can be used to monitor your voltage. The accuracy of the readings can be off, so they are best used to check consistency. If your system has been running great, and then you install Motherboard Monitor, and it shows that your +5 is 4.72, that is no reason to panic. It would be a reason to try to verify that reading with a meter. If the meter showed your +5 to be closer to spec, then you could factor in the inaccuracy. But if it started to drop, and you began to have lock ups, you'd know that you had a problem.

Re: Re: How can you tell if a PSU is a limiting factor in OC'ing?

dustybyrd said:

your chip already seems to be at the upper limits of likely speeds...2.4ghz! with already very high voltage...

if i were you, try to find a more powerful supply to test the system with and see if it adds to the overclock...but i doubt it...

that said, you are probably overloading that psu...particularly if your mobo supplies the cpu with power through the 12v line...

if you must upgrade, then get the fortron 530 or antec tp 480, 550...since the fortron 350 would be an upgrade...but not a big enough upgrade for the price

Click to expand...

Yes, I've seem to have hit the limit of my chip. It won't go above 2.4 no matter what I try.

I was thinking of just grabbing a Fortron 530 when Newegg has some refurbs. If nothing else, the new PSU will give me headroom from expansion.