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ATI 5870 - PSU Question

deadfolk

deadfolk

deadfolk

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Joined
28 Jan 2005
Posts
237
Location
Ireland
Hi All,

Just a quick one...it looks like the new whizz-ban Radeons take two 12v inputs. My PSU only supplies two, and one is already used by my M/B.

Is okay to use a splitter, or is that a really stupid question and I need to just STFU and get a new PSU?

Cheers,

DF
 
It's an Enermax EG495AX-VE(W)(24P).
It's 485W.
It says the 12v rails are 18A.

Since posting my first message, I noticed that OCUK don't seem to stock a splitter for the 12v cable anyway, although they do have one with a female molex (or two - it's hard to tell in the pic) like this, although I thought that would only give you 5v, so I don't know if that would be of use.
 
The graphics cards use special PCI-E power connectors. If your PSU doesn't supply two of these, it's unlikely it has the grunt for such a card. Older PSU's are less powerful on the 12V rails than their newer cousins.
 
All power supply models are different, on paper a power supply may look great but in practice be weak and vice versa, you won't know until you try.
 
18a wont be enough
although if you put one 6 pin adaptor on each rail it might be ok, but i have no idea of the amps that are required for a 5870
 
Recommended Power Supply
So here's my power supply recommendation:

Radeon HD 5870

The card requires you to have a 500 Watt power supply unit at minimum if you use it in a high-end system. That power supply needs to have (in total accumulated) at least 40 Amps available on the +12 volts rails.
Radeon HD 5870 CrossfireX

A second card requires you to add another 188 Watts. You need a 700+ Watt power supply unit if you use it in a high-end system. That power supply needs to have (in total accumulated) at least 55~60 Amps available on the +12 volts rails.
For each card that you add, add another 200 Watts as a safety margin.

http://www.guru3d.com/article/radeon-hd-5870-review-test/13
 
Ch3m1c4L said:
18a wont be enough
although if you put one 6 pin adaptor on each rail it might be ok, but i have no idea of the amps that are required for a 5870
Click to expand...

5870 pulled 160W under furmark.

160W/12V = 13A - but of course, you have to remember that unless you have a seperate 12v rail for GPU, a few amps will be taken for the HDD, DVD, fans, etc.

The Guru3D data posted by lemin suggests 200w:
200w/12v = 16A.

Which is seriously close to the bone.

You really want to get a new PSU to be sure if 18A is all you have - no point putting in a £300W GPU onto an old PSU IMHO, especially one that appears to be pretty close to the limit on the cards specs - the BeQuiet one that Superewza looks spot on for the job - although I'd be looking for a modular one, if ony because it helps keep things tidy inside :)

[unless my maths have gone wrong, arf]
 
I've been using a Silverstone 560W ST56ZF for the last few years and it's powewed every single GPU card in existence. It has 38A on a single rail.

500-600w PSU's should be able to handle a single card, but it depends on the 12v amps available on the rail powering the card more than the overall watts.

If you look at overall power usage in reviews, single cards with multi core cpus rarely go over 300-400W max. I bet the 5870 isn't any different.
 
It has 2 x 18A +12v rails, If both can be run at full load together 36A it would be ok.

But if they have seperate overload protection you might have a problem, unfortunately cause it's a few years old it's hard to find the relevent infomation.

You need 2 6-pin PCI-Express video connectors, you can use an adaptor from 2 molex pugs to 1 6-pin PCI-Express, the +12v line that goes to your motherboard is different.
 
Hmm...

Well, I'm running 5xHDD, 1xDVD and an oc'd Quad-Core CPU right now. I guess adding one of these babys might put me over the limit.

It would break my heart to get the card and not be able to use it due to my PSU, and to be honest, it probably wouldn't hurt to get a new, modular one anyway, as the inside of my PC looks like someone threw up in it...and it has a transparent window on the side!

I might just go for the PSU now and then start saving again for the card. Those modular BeQuiet ones look pretty sweet...and who knows - the cards might come down a little in price once the initial rush wears off.

Thanks for the input, all.
 
the main thing is, are you comfortable putting a £300 card on a £25 psu that could take the lot with it when/if it goes?
getting a quality psu now allows for upgrades and gives peace of mind :P
 
the main thing is, are you comfortable putting a £300 card on a £25 psu that could take the lot with it when/if it goes?
getting a quality psu now allows for upgrades and gives peace of mind :P
Click to expand...

Well, it wasn't a cheapie when I got it a few years back!:p

But the point is a good one. Decision made. New PSU now, new GFX card later.

It's just a shame - the PSU is the single least exciting thing you can upgrade.:(

(I'm such a kid!)

Thanks again.
 
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