8800 gtx support 620w psu

[George Hallam]

i have a 620w psu will this be ok for the 8800gtx or do i need more power

[jlreich]

We need to see the specs on the rest of the system. :)

[mjc]

And the make/model of the power supply...not all 600+ W PSUs are created equal.

[George Hallam]

Corsair HX 620W ATX2.2 Modular SLI Compliant PSU

i have on now;

intel core 2 duo 2.13ghz
GeIL 2gb 800mhz
BFG 7950gt
abit AW9d max

[alex666]

I've had very similar concerns, as I'm waiting for a 8800gts to arrive on Monday. I've been all over the internet checking out voltage requirements. The 8800gts will be placed with a biostar 6100/410 mobo running a venice 3500 oced to 2.7GHz and 2 X 512 OCZ plat. rev 2 memory, 2 hdds, one optical, and maybe one sound card. I also may increase my ram to 2 X 1gig.

I'm going to be using a 610W Silencer by PC Power and Cooling for my psu. I opted for this because it only has one 12 volt rail rated at 49amps. I've become leery of these split rail psus, having been burned by a neopower 480 with split rails that had insufficient juice to run my x2 4200 on my soltek mobo. It also seriously limited my ability to oc my venice 3500 on the biostar. Note that when I replaced the neopower with an enermax liberty 500W in my soltek system, it ran the x2 4200 without a burp and continues to do so for 4 months now. I also temporarily put the enermax liberty into my biostar system (which had been using the neopower) and obtained a much much better oc. Note that the voltage readings on the 3, 5, and 12 volt rails are well within spec. It just goes to show that wattage per se is really not a good measure of a psu's capabilities.

I'll post back when I get my system up and running. The 8800gts arrives Monday, and the 610 Silencer on Monday or Tuesday.

marty

[jlreich]

620W should be enough if it is a quality PSU. And you have only one maybe two standard hard drives and not a lot of other extra components. If you plan on adding in more drives or a WD Raptor, TV tuner or anything like that you might want to think about going higher.

Alex666, I was talking to Saphalline not long ago about the 12v rail thing. Here is an excerpt from our conversation. I hope you don't mind Saph. :)

...you can't expect a $100 Antec PSU to perform equally to a $600 PC Power & Cooling PSU! Just because the PC P&C uses a single +12V rail doesn't mean the cheaper PSU's (which most people buy) can get away with the same thing. Stability is an issue.

The whole idea of multiple +12V rails was to stabilize each rail for sudden loads, like going from idle to gaming. Normal quality PSU's in the $100 range don't have the high quality components that PC P&C uses (again - cost) and so the single rail stability is just not an option! Just because it's the "best" way to go doesn't mean it's the most cost-effective way to go.

[saphalline]

jlreich - Nah, I don't mind.

alex666 - The Antec NeoPower series of PSU's really sucked. Not up to standard Antec quality at all! Too bad you had to cut your teeth on that one! :p Multiple +12V designs are not inherently flawed - they've just gotten a bad name because so many PSU's are horrible. I've never had a problem with them, but then again I know how to pick them out.

George Hallam - That Corsair PSU will be fine for a GeForce 8800 GTX, as long as you dedicate one of the +12V rails to the vid card. At 18A per +12V rail, you've got more than enough power for your system. But a single 8800 GTX eats up 165W of +12V power (peak). So give it an entire rail and you won't have to worry about stability issues.

[alex666]

George Hallam - That Corsair PSU will be fine for a GeForce 8800 GTX, as long as you dedicate one of the +12V rails to the vid card. At 18A per +12V rail, you've got more than enough power for your system. But a single 8800 GTX eats up 165W of +12V power (peak). So give it an entire rail and you won't have to worry about stability issues.

How do you do that?

[saphalline]

Just read the wiring diagram for the PSU. The separate +12V rails are dedicated to certain physical wires coming from the PSU. For instance, on many of the modern high-end triple/quad +12V quad-SLI rated PSU's (the 650-850W monsters) there are four 6-pin PCIe power connectors. There's a +12V rail dedicated to each pair, with the remaining +12V rail(s) dedicated to the rest of the system. The multiple +12V rail PSU's have already done the work of separating the power with the wires. You just have to read the wiring diagram to figure out where they're all going.

[alex666]

Just read the wiring diagram for the PSU. The separate +12V rails are dedicated to certain physical wires coming from the PSU. For instance, on many of the modern high-end triple/quad +12V quad-SLI rated PSU's (the 650-850W monsters) there are four 6-pin PCIe power connectors. There's a +12V rail dedicated to each pair, with the remaining +12V rail(s) dedicated to the rest of the system. The multiple +12V rail PSU's have already done the work of separating the power with the wires. You just have to read the wiring diagram to figure out where they're all going.

Yes, I'm aware of the above. But when you said the following: "as long as you dedicate one of the +12V rails to the vid card", it's not like the end-user can somehow manipulate or take some action to "dedicate" one of those rails to the video card. It's already set up that way.

[saphalline]

In a sense, yes. But this is exactly why I pick my PSU's more carefully than my car tires! There are just way too many cr@ppy PSU's out there to just give pointers on what to look for. I don't know anyone else who puts more research into PSU buying than me. I make darn sure that the wiring diagram even exists before I consider a particular PSU! And after so many gaming systems, you learn a lot about what it takes to make a stable electrical environment.

Now I couldn't find a wiring diagram for George Hallam's Corsair PSU, so I carefully worded my response, using the word "should" instead of being definitive. There's a reason I wouldn't plunk down my seal of approval. The PSU arena hasn't caught up to the quality that we've come to expect from just about every other computer component. From fans to RAM, most components are covered by simple guidelines, but PSU's still have to be hand-picked for gaming.

[alex666]

Yep, there is still a lot to be desired on how to pick a psu. I spent a long time before I got the enermax liberty 500W, and I've been quite pleased. I'm going with the 610 silencer largely on the rep of PC Power and Cooling, but also from what I was able to glean from their downloads. I'm not enough of a techie to fully understand schematics, however.

marty