BleepingComputer.com: Video Card Upgrade leads to Power Supply Upgrade - Compatability Check

This problem I have all started with me wanting to upgrade my video card. I then learned my PSU's specs are awful, and a new video card wouldn't run with out a new PSU...

This is my current PSU's specs (awful):
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300W

+5V @ 25A +12 @ 19A +5sb @ 2A
+3.3 @ 18A -12 @ .8A
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So I'd like to upgrade, but the problem I'm having is figuring some things out:

1.)Do I need to see all the rails listed above with the same amps or better in the new PSU's specs?
2.)What if the PSU I want to buy is missing the specs for a rail? or in other words, I have to have all the rails listed in my current specs, correct?
3.)Will the new PSU use all the same inputs on my motherboard?

Let's take an example:

XCLIO DIAMONDPOWER 680W

Output: +3.3V@28A,+5V@30A,+12V@54A,-12V@0.5A,+5VSB@4.0A

Connectors:

1 x Main connector (20+4Pin)
1 x 12V(4+4Pin)
8 x peripheral
8 x SATA
1 x Floppy
4 x PCI-E

I've hilighted in red what I think is a problem. As far as I know, just having the total wattage exceed your old PSU isn't enough, all the rails need to be the same too (or better) (I think ?)




The current machine I have is from a few Christmases ago; an OEM machine from Circuit City.

The HP Pavilion Elite m9040n.

This is its motherboard:

Click for complete specs and diagrams


The mobo only has PCIe x16, so

1.) Is it worth it for me to buy an NVIDIA GTX 260 if I can't utilize all the bandwidth of a 2.0 card?
2.) Would buying a 9800 GTX do the same because of the bandwidth cap?
3.) Would there be a cap, or in other words, does the 260 use all the PCIe x16's bandwidth?
4.) Do I have the correct power connection for such a high end card?


I think a lot of the questions I have can be answered by simply knowing the specs to look for, but I obviously don't know what to look for. Again, I apologize for being so clueless, I've done hours of research spread out over the course of a few weeks and I've figured out a lot, but I'm just not able to find clear answers to these questions anywhere. Any help answering any one of these questions or all of them is greatly appreciated!

This post has been edited by GraysonH: 23 June 2009 - 03:40 PM

When purchasing a power supply, buying one from a good company is best. Almost all power supplies that are rated SLI or Crossfire certified have the necessary rails and amps. For a GTX 260, the CORSAIR CMPSU-650TX 650W or the PC Power & Cooling S61EPS 610W will meet your needs. As for your questions....

1. Don't worry too much about PCI-express x16 2.0 as the card is backwards compatible. The GTX 260 will still perform well under the 1.0 spec.
2. A GeForce 9800 GTX also uses a PCI-express x16 2.0 slot too. The GTX 260 will still be a superior card regardless of the PCIe spec, see here.
3. I would be more conerned with the CPU creating a bottleneck before the PCIe x16 reaches it's maximum bandwidth. Depending on the application, you may not need the increased bandwidth 2.0 offers.
4. The appropriate power connections are found with the power supply and are not on the motherboard. The power supplies I suggested have all necessary electrical hookups to work with any graphics card.

Tom's Hardware - PCI Express 2.0 Graphics Cards Tested <<<They test GPU's to see how much of an advantage PCIe 2.0 offers over 1.0.

Thank you very much DJBPace07, those two PSUs you recommended might just save me a bit of money! If anyone else has any other information or a different take on my questions that'd be greatly appreciated, but I think DJ's got it all.

Not much to add to the above post. Your motherboard/videocard is mainly dependant upon the +12V rail. That is the one that really matters, and carrys the main load on a system. The "-" voltages aren't even used anymore. The +5V is used mainly for standby purposes (and floppy disk drivers if so inclined).

http://www.jonnyguru.com/ is a good place to start when researching power supplies.