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Got a buddy wanting to upgrade to a HD 5870 (and overclocking it, of course). He asked me if his power supply was adequate and I said it was fine. It's a OCZ ModXStream 600 watt with two 12v rails at 25amps each, for a total of 50amps. I'm not too concerned about the watts as I know that's plenty, but it's more about the amps I have a question about.
 

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It will be plenty. OCZ underrates their PSUs heavily (as in the 600 GXS is actually 864 on the 12v rails alone.)

Just be sure its distributed well.
 

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Not the best PSU out there but it will due.
 

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So you know, at a constant voltage (which it is always the 12v on pcie cards), increased amps = power linearly.

25A x 12V = 300W

If you had 1/5 the amps on the line you'd get 1/5 the power.

5A x 12V = 60W

Since you know the amps and voltage you know if it'll run the wattage you need.
 

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You don't just add the rails together to get the total maximum output. It actually has a total output of 42A/504W, not 50A/600W.

But yes, that power supply will power the HD5870, but I wouldn't really recommend that PSU to be honest. It's based on a pretty... bad Sirfa design. Not cool, yo.

By the way, the HD5870 (at stock) will draw about a maximum of 13A from the 12V rail. This is excluding Furmark, obviously.

Quote:

Originally Posted by foothead View Post
It will be plenty. OCZ underrates their PSUs heavily (as in the 600 GXS is actually 864 on the 12v rails alone.)

Just be sure its distributed well.
864W eh? That's not true. At all.

The 600W GameXstream's not even a good power supply. Load it to 600W at 40C, and you're going to get voltage ripple barely within ATX Spec. Load it much further and you're going to get ripple way out of spec, potentially killing hardware.

Where'd you get 864W from...?

It has 44A/528W on the 12V rail, despite what you said...

Quote:

Originally Posted by Dream Killer View Post
Considering that ATi is recommending a 600w PSU for a crossfire setup, that should be more than adequate for an overclocked CPU + overclocked GPU.
 
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