Installed new PSU, now old OC settings won't work

[franklin411]

Hello, it was suggested that I post in the PSU forum, so here I am. I have a Gigabyte P35-DS3L mobo with a 6750 2.66 processor, 4 gb of PC2-6400 CL4 ram, an Nvidia 7800 GTX OC, 2 SATA HDDs and a SATA DVD burner. I had the system running stable overclocked to 3.2 GHz and I was using a PC Power and Cooling 510w PSU. I did not need to change much to get the OC to work--I just increased the bus to 400mhz, and changed the memory speed settings accordingly. Didn't have to play with the vcore settings.

I recently sold the PSU because my old case was beaten up and the PC Power and Cooling PSU sounded like a jet engine at take off. It had to be running at at least 50+ db. I got a new case with an Antec 500w Earthwatts PSU, but when I hooked it all up, the system was unstable. I would get random crashes, system error messages ("Explorer has encountered a problem and needs to close"), corrupted files in Windows, and sometimes I couldn't even boot into Windows for multiple consecutive attempts.

The only hardware I installed between when the system worked and when it didn't was the Antec PSU, so I'm wondering if that could be the culprit. I downclocked the system back to stock and it seems to run fine, but is it possible that the system would work fine with one 500w PSU and not work at all with the same settings with another 500w psu? It doesn't seem like I'm pushing the edge of the envelope as far as power is concerned. I'm thinking I probably just didn't OC it properly in the first place, but it still seems odd to me that it would fail exactly when I installed a new PSU--I had been gaming for about 4 hours in the morning, then my package arrived and I swapped over, and then it wouldn't work.

Thanks!

Edit: I also read that the Earthwatts 500 has two PCI-E connectors: one for 380 and 420w cards, and one for 500w cards. The manual doesn't say anything about this, and the connectors are identical. I also switched the PCI-E connector I was using, figuring it couldn't hurt.

 

[jonnyGURU]

Originally posted by: franklin411

Edit: I also read that the Earthwatts 500 has two PCI-E connectors: one for 380 and 420w cards, and one for 500w cards. The manual doesn't say anything about this, and the connectors are identical. I also switched the PCI-E connector I was using, figuring it couldn't hurt.

That's wrong. There are no 380w. 420w and 500w cards. Cards that have one PCI-e connector are 150W, cards with two PCI-e connectors are 225W and cards with one 6-pin and one 8-pin are called 300W cards.

The PCP&C has better voltage regulation and less ripple and noise than your Antec, so it stands to reason that using a quality power supply unit helped your overclocks.

Of course, we could hope that you just have a flaky unit and an RMA for another one will resolve the issue.

 

[franklin411]

K...I think I got this. I downloaded everest and immediately the system failed the memory test at OC settings. I have two different sets of ram in this system: Corsair XMS2 6400 CL4 @ 2.1v and Patriot Extreme 6400 CL4 @ 2.2v. Everest was giving me a dimm voltage of 2.06v when I had the BIOS set to +0.4v (which should give a vdimm of 2.2v). I pulled the Patriot ram and the system ran fine, mem tested fine. I already tried running both sets of ram closer to 2.2v (measured) but that won't work either.

So my guess is that the PC Power and Cooling PSU was probably giving me a voltage that both sets of ram could live with, while the Antec is giving me a voltage that only one of them will work with. The system is running stable now OC'ed with only the Corsair memory installed.

I'm left with a choice of accepting the memory at CL5 since both will run at 1.8v at that speed, or replacing the Patriots with Corsairs and sticking w/ CL4. Are you kiddin? I'm going with the CL4!

Thanks for the help!