Another Will This Be Enough Power Question

[toy4x4]

Ok, I would love to know how to figure out how to find the specs for how much power my stuff requires. I looked around the forum and didn't find much on how to figure it out. Feel free to just point me in the right direction. Anyway on to the question..

I have just ordered 2 7800GTX 256 cards to SLI in the machine(long story, but yeah!) and it got me thinking on whether my power supply will drive everything. Here is what I have:

PC Config:
SeaSonic 430W PSU
ASUS A8N-SLI Premium
AMD Athlon 64 3700+ San Diego
XFX 7800GT 256
CORSAIR XMS 2GB (2 x 1GB) DDR400
2 x 36GB WD Raptor
2 x 300GB Seagate SATA
NEC 2500A CD/DVD

I do have a Ultra X-Connect 500W sitting in the closet. I prefer the Seasonic because it is a little quieter, but I would switch if I need to and it is enough.

[<<Spider>>]

I think I just answer this a few minutes ago somewhere else.

Anyway, most of the time when a computer crash due to power is because of the 12V rail. Just look at the 12V rail and make sure you have enough power for your CPU and video card. Your CPU and Video card takes up about 97% to 99% of the 12V rail.

The San Diego will use more power, the more you overclock and the Vcore you put on the CPU. It's hard to determine how much power you are using on the CPU. Run Sisfoft Sandra CPU burn test and it'll show you the wattage it uses. At very extreme overclock, it may need 150W so let say 110W is good.

The video card 7800GT does require a bit more wattage then his brothers. You will need more than 100W. Maybe 150 to be safe.

Taken these two put together, you'll need about 260W on 12V rail. Aprox 22A of clean power. Power supply is only efficient at 70 to 80% max so you'll have to up that number a bit. About 32A if your pSU don't have active PFC and 26A if it has Active PFC.

If you have dual 12V rails, seperate one for the CPU and the other for the Vid card and system. Calculate it to see if it is enough.

My advice if you are doing 7800 SLI is to get something with at lease 33A and active PFC.

[stereo555]

This should help you ..... LINKY (http://www.extreme.outervision.com/index.jsp) :cool:

[toy4x4]

Both excellent replies!!

Looks like it's a no go with the 430W Seasonic but barely able with the Ultra 500W. At least i know where to begin!

thanks!

[Know Nuttin]

Don't buy a 500w Ultra. Spend your money on a different PSU altogether.

Your Seasonic would be very hard pushed with the hardware you have listed.

What is your budget for a PSU?

[DeepScience]

Don't buy a 500w Ultra. Spend your money on a different PSU altogether.

Your Seasonic would be very hard pushed with the hardware you have listed.

What is your budget for a PSU?

He doesn't need to buy one, he was thinking about coming out of the closet with one.

OCZ520powerstream or whatever wolf says next... :D

[Oklahoma Wolf]

Since silence seems to be a concern to you, I'll go against my usual advice and suggest the Seasonic S12 600W. The dual 12v topology may limit overclocking, but these things are rated at 40 degrees so it should still be ok.

In the single 12v units, only the Powerstream 520W really has the chance to be fairly quiet. The Silverstone Zeus 560W would be my next choice from there from a silence standpoint, being more efficient with bigger heatsinks than most of the others. However, I don't know for sure how loud the Silverstone is yet.

[Know Nuttin]

There are better things to come out of the closet with :P

nVidia spec's the 7800GT's at around 100-110w. That would be roughly 9A of +12v/card, assuming all of the power is given by +12v, which I don't believe it is. A large portion of it is +12v though, and better to err on the side of caution.

Stay away from dual +12v units with your setup.

The usual suspects are the OCZ Powerstream 520w SLI, the Silverstone 560w ST56ZF, Sparkle FSP550PLG-SLI, or the Zippy Gaming 500/550w. I can't attest to how quiet the Zippy is (I can't find one to order) or the Silverstone. The OCZ is probably the quietest out of the ones mentioned.

[<<Spider>>]

Here is my suggestion. Sparkle 550. 36A on 12V rail and active PFC. Much cheaper than Powerstream 520w SLI.

http://www.ewiz.com/detail.php?p=PS-SP550SL&c=fr&pid=4dfc7fe6724c8818729f6f16e6543d3ab9a57664da7b3a 18641b9d4d3ab11a27#

[toy4x4]

thanks for the great info and dialog!

As for budget, I blew the heck out of that a week ago. So far I'm out about $2500 on the new rig. Only thing I have not replaced is my case, power supply, keyboard and mouse. Add in the 24" LCD panel and I am going to have to wait until next month before getting a new power supply. Hopefully the Ultra will work and if not, I'll probably temporarily run a dul power supply solution until I get over the wanting to puke factor with buying something else...

[Seanohue]

This should help you ..... LINKY (http://www.extreme.outervision.com/index.jsp) :cool:
That really needs to be stickied.

[BrutalDrew]

Are you overclocking? I know this is OCForums, but not everybody does. If you are not the Seasonic may be fine.

[toy4x4]

Not OC anything. Will in the future, but the plan then would be to go water cooling and I know I need a new power setup then.

What am I going to experience if I don't have enough power? That way I know what to look for.

[DeepScience]

Not OC anything. Will in the future, but the plan then would be to go water cooling and I know I need a new power setup then.

What am I going to experience if I don't have enough power? That way I know what to look for.

Random reboots and crashes, especially if pushing that video card hard in a game.