Budget Build using a 400w PSU + GTX 560

[Lone Ranger]

I'm helping a friend build a budget gaming system. I'd like to use a 400w antec PSU I have lying around to help free up some money. However, is the PSU the wrong place to save money, considering we want to get a GTX 560? The specs require a 450w or greater.

We'll be using a 65w intel i3, so there won't be any overclocking going on. This could theoretically save the 50w that I'm lacking (at a minimum) to run such a video card. Any thoughts?

 

[blastingcap]

I'm helping a friend build a budget gaming system. I'd like to use a 400w antec PSU I have lying around to help free up some money. However, is the PSU the wrong place to save money, considering we want to get a GTX 560? The specs require a 450w or greater.

We'll be using a 65w intel i3, so there won't be any overclocking going on. This could theoretically save the 50w that I'm lacking (at a minimum) to run such a video card. Any thoughts?

Video card makers are extremely conservative with minimum PSU specs in order to account for bad PSUs. You have a decent PSU.

You have way more than enough power for a GTX 560, assuming that your 12V rail can supply enough amps, but Antec usually has pretty good PSUs and I would be shocked if they didn't have at least 24 amps on the 12V rail.

You have these theoretical maximum wattages:

10 watts per hard drive or optical drive
30 watts for the motherboard including RAM
10 watts for peripherals like USB mice/keyboard and for case fans
65 watts for the CPU (drawing 5.5 amps on the 12V rail)
50 watts cushion room in case of aging capacitors or whatever else
-----
175 watts total

From where I'm standing, you have only ~125 watts power draw if you have one hard drive and one DVD/CD-RW drive, and even with a 50 watt cushion that's still just 175 watts. Even if you install 3 more hard drives and somehow got all of your hard drives and optical drives to be active at the same time as your CPU is getting maxed out, that's only +30 watts, for a total of 205 watts.

It's virtually impossible for every component to max out at the same time, so realistically you will never actually hit 200 watts in such a system. (See system power draws in video card reviews for proof of this.)

So basically you have about 200 watts left over for your video card, or whatever capacity is left on the 12V rail after the CPU takes its 5.5 amp cut. That's more than enough for a GTX 560... way more. You could overclock the hell out of it and still be fine.

 

[aaksheytalwar]

Antec psus vary greatly in quality, just like cooler master. Their top end competes with Seasonic and corsair, or at least nearly. But their low end will barely give half the rated power. IMO get a quality 550-600 watts for the future. And it all depends on the exact model of your current psu but I wouldn't recommend it no matter what

 

[BD231]

I'd go with your plan as long as you know that PSU isn't really old. I bought the highest rated no name $20 dollar 500watt PSU on newegg three years ago for an old system I had that actually ended up going into a gaming build for someone and he's still using after 2 gpu upgrades and 1 cpu change. Told him use it at your own risk but it's been a performer so 300 watts and under shouldn't be hard at all for even the sub-par Antec psu.

If you could post the model type that would be helpful.