PSU question

[Warhawk]

Hey guys,

Working on my friends gateway computer. He got an amd x4 9500 cpu and a 4850 in a gateway desktop. The PSU he is running is a antec Basiq 500 watt with 18 amps on the 12v rail. Anyway, when playing games sometimes the computer reboots. I'm not totally sure what the problem is but I think it could either be the PSU or overheating. Any ideas?

[=98=]

Re: PSU question

Could well be an underpowered PSU.

[CptainCrunch]

Re: PSU question

I would also say its the PSU. I had the same issue with a "500W" supply. Come to find out it was 500W Max and actually ran at 350W.

Crunch

[Wizrdwarts]

Re: PSU question

An 8800GT recommends 26 amps on the +12v rail. Even if the 4850 is more efficient, 18 amps can't be enough to run well.

Never buy PSUs for wattage alone, look at the amperage for the rails, my Corsair 450w has 33 amps on the 12v rail.

[Jazzman]

Re: PSU question

can i get the corsair 450 w for a palit oc 4870

[Wizrdwarts]

Re: PSU question

Start your own thread. :shakehead:

Anyways, you would be pushing it on a 450, I'd get the 550 just to be safe.

[Warhawk]

Re: PSU question

yeah I didn't think 18 amp was enough to be running a 4850. I'll see what I can do. Plus its one of those Antec Basiq PSU's. In other words, its not meant for a gaming system.

[Busby, Paul (Bicci)]

Re: PSU question

I would also go for the 550W corsair if i had a 4870, just to be safe.

That basiq PSU doesnt have enough grunt for that system by far! The 450W corsair one should be fine for that system though. Its not just the Amps on the 12V its the watts across the 12V rail(s)

[AlecJ32]

Re: PSU question

There's no need to get the VX550 'just to be safe'. The VX450 should power the card just fine.

Let's have a look-see at your friend's current power supply.

18 amps * 12 volts = 216 watts, so there's 216 watts of power available on the 12 volt rail. 216 watts - 95 watts (CPU) = 121 watts for the rest of the hardware. Now, I don't know how much power the 4850 uses, but it's probably between 110-130 watts, so it's definitely possible for it to be a power supply problem. (Let's remember, those parts probably aren't going to be drawing full load all the time)

[Busby, Paul (Bicci)]

Re: PSU question

There's no need to get the VX550 'just to be safe'. The VX450 should power the card just fine.

For a 4870 i would feel more comfortable with the VX550, gives more space for upgrade

[=98=]

Re: PSU question

Yes, for a 4870 i would definitely recommend at least a 500W, quality PSU.

[AlecJ32]

Re: PSU question

For a 4870 i would feel more comfortable with the VX550, gives more space for upgrade

Let's do some math, shall we?

33 amps * 12 volts = 396 watts. That's an awful lot of power. I don't know how much power a 4870 uses, probably no more than 150 watts, but let's be extremely conservative and say it uses 200 watts. Even then, that'd leave you with 196 watts for the rest of your hardware. I believe that Phenom is 95 watts TDP, so it can't use more than 95 watts of power. You'd be left with 101 watts for the rest of your hardware, and that should be enough headroom.


A better reason to recommend the 550VX is that Corsair's power supplies have 5 year warranties, and you probably won't use the same video card for 5 years. That means you could use the 550VX further down the road should you upgrade to a hungrier video card.

And really, the 550VX is what, $10 more? It wouldn't be a bad buy at all.

[Jazzman]

Re: PSU question

on amds website it says minimum 500 for the 4870

[Warhawk]

Re: PSU question

Ok but doesn't the 4850 pull less power than a 4870 or no??

[Wizrdwarts]

Re: PSU question

Yes, but 18 amps is really low to be running any sort of high performance graphics cards on it.

ATI/AMD's site just says a 450w PSU, why can't they be more specific with amps?