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Enough power?

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FlakMonkey

Member
Joined
Aug 6, 2005
Location
Milwaukee
Hey all, I'm gonna be purchasing a couple upgrades in the near future and want to be sure my PSU will be able to handle the added power. Here is my hypothetical setup:

Asus P5B-E
Intel Q9400
VisionTek HD 4890
2GB OCZ RAM
3 x 7200rpm HDDs
1 x DVD-RW
Creative Audigy

running on this Corsair 450W

The HD4890 lists a 500W as a requirement but I've also read that my PSU can handle more. Assume no OC. Thanks in advance for any advice.
 
Hey all, I'm gonna be purchasing a couple upgrades in the near future and want to be sure my PSU will be able to handle the added power. Here is my hypothetical setup:

Asus P5B-E
Intel Q9400
VisionTek HD 4890
2GB OCZ RAM
3 x 7200rpm HDDs
1 x DVD-RW
Creative Audigy

running on this Corsair 450W

The HD4890 lists a 500W as a requirement but I've also read that my PSU can handle more. Assume no OC. Thanks in advance for any advice.

Flak,

You're really pushing it at a full load at stock. That Corsair only has 1 6 - pin connector, you need two for that 4890.
 
Running the system in my sig, stock clocks on both CPU and GPU, also with 3 hard drives and 1 optical, it's sucking down (roughly) 304 watts from the PSU, 380 at the wall as per a Kill-A-Watt. That's while running Prime95 and Furmark at the same time.

During real gaming use, even on UE3 stuff which is a power hog, the Kill-A-Watt only reads 290-300 watts, which assuming 80% efficiency, translates to 240 watts or so.

Your video card is a tad less thirsty, and the CPU maybe a bit more, so I'd say that PSU is well within its capability to run that system during normal use. The PSU will probably be running at about 60-70% of its rated capacity which is just fine, and not overspeccing the PSU means that during idle times, it'll be running that much closer to the sweet spot of the efficiency curve.
 
Flak,

You're really pushing it at a full load at stock. That Corsair only has 1 6 - pin connector, you need two for that 4890.

Ah thanks for pointing out the 6-pin bit, I completely forgot to check that. An adapter like this or this would work, right? Really trying to avoid a new PSU.

When you say pushing it, does that mean it will work as long as I don't touch anything and leave it all at stock? Or do I not want it to get close to the 450W even at 100% load on the CPU and GPU. Pardon my lack of knowledge in this area :].

Running the system in my sig, stock clocks on both CPU and GPU, also with 3 hard drives and 1 optical, it's sucking down (roughly) 304 watts from the PSU, 380 at the wall as per a Kill-A-Watt. That's while running Prime95 and Furmark at the same time.

During real gaming use, even on UE3 stuff which is a power hog, the Kill-A-Watt only reads 290-300 watts, which assuming 80% efficiency, translates to 240 watts or so.

Your video card is a tad less thirsty, and the CPU maybe a bit more, so I'd say that PSU is well within its capability to run that system during normal use. The PSU will probably be running at about 60-70% of its rated capacity which is just fine, and not overspeccing the PSU means that during idle times, it'll be running that much closer to the sweet spot of the efficiency curve.

Thanks a lot for this, really good insight. Would I be safe with a 450W then? I'm not sure what sort of headroom I should be leaving.

EDIT: Thanks for your help guys, I decided to go another route to assure my PSU will run then while also saving some money.
 
Last edited:
If your PSU is a single rail, then the 4pin-molex to 6pin PCI-E adaptor will work. This is because some multi rail PSUs give little amps to the 4-pin wires. I believe the Corsair 450VX is a single rail, so it should be fine.
 
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