600W Overkill?

[dangel]

That's AC though, right?

It's measured wattage at the socket yup (and therefore paid for..)

[sammorris]

True. I tend to consider the DC load as it is what decides which PSU someone needs. I factor AC in when calculating electricity costs (i.e. why you don't want to buy inefficient product X,Y,etc.)

[dangel]

Problem is, it's difficult (DC draw) to measure (unless we go on manufacturers stats alone) in reality - at best it's an estimate versus a meter reading which is maybe a few % out max. But yeah, i'd do the component 1 + ... = psu needed thing for a ballpark figure and then look at individual rails, efficiency etc. The HX1000 is sitting in it's efficiency zone for me which is a plus, and i can't knock it for connectivity/quality or the ability to scale up to qual sli should i really lose the plot in the future..

[sammorris]

Agreed, I use rough efficiency figures from PSU reviews (ons that use 240V are hard to find sometimes) and apply them to the AC input, it's usually not too far off.

[Shedlife]

I doubt any 450W PSU is designed for dual graphics cards...looks like 600W StealthXStream or 500W ModXStream

[sammorris]

The 450HX has the two 6-pin connectors required and has ample power to do it. Remember, my system only drew 380-390W from the PSU when running a 3.8Ghz Q9550 and an HD4870X2. Contrary to popular belief, dual graphics does not mean a silly power supply is needed.

[Shedlife]

So aslong as it has 2 or more 12V rails, the PSU should be good?

Edit: Just went to Antec's power supply calculator, and it came out at 420W. I'm thinking I'll invest in a 500WStealthXStream

[shadowmaster]

So aslong as it has 2 or more 12V rails, the PSU should be good?

Not necessarily, some good quality psu's such as the corsair vx450 have single 12v rails. And some crap such as Ezcool have dual rails.....

TBH your system can get away with a good quality for 400watt+ psu as I doubt your system will consume more then 320watts at load. However just be a little on the safe side I would probably go for a 450watt+ psu. So the corsair vx450 or the ocz 500watt are good choices. Alternatively any psu from one of the top manufacturers will do you fine (enermax, seasonic, fsp, corsair, ocz, etc)

[sammorris]

The number of rails really is irrelevant. A lot of people swear by single-rail PSUs, I don't really mind either way. The 420W from the Antec PSU calculator is, like all PSU calculators, a massive overstatement. The VX450 or OCZ500 are far more than sufficient. The HX450 is probably among the best PSUs you can buy for that wattage, but it's not available in all countries, and is quite expensive.

[Shedlife]

is quite expensive.

Yeh, thats why I wanted to double check because the whole idea of this system is to get a PC that can play Crysis (at playable FPS 40+) for as little as possible, aswell as being as future proof as possible. Which considering the £500 budget includes a screen, I think is pretty darn well good

[ezekiel 08]

A 500w PSU is good as it will still work even if you upgrade you rig. Even high end systems can still use under 500w, you'll be surprised!

[sammorris]

Case in point a 3.87Ghz Q9550 with an HD4870X2 and three HDDs using 420W...