What PSU is recommended for 2 Sapphire HD 4890 2GB CrossFire

Hello,

Ok you know even us pros get thing wrong and at times we tend to forget simple thongs. So here is what probably is a dumb question but well worth asking.

Q: I'm thinking of getting two Sapphire Vapor-X 2GB cards and crossfire these together. Now my main concern is power. I have calculated three times over and I think I am right with my figures I have a new ENERMAX Revolution PSU although the PSU is 850W with a Peak Power of 1020W and a UPS of 1000W/1400VA and 12V Rail is 70A this should be more than enough to handle two 2GB cards?

If not I'm more than happy to settle with one.:)

Thank you and thgin doog (read it backwards):rolleyes:

My similarly spec'ed rig uses no more more than 560W (700W from the mains) so I have no doubts that the 850W PSU will suit your needs just fine.

I agree, a good quality 700watt psu will handle it fine, so it should be no problem for an 850watt Enermax. :)

So in simplest terms... :stupid:

I did say it wad a stupid question mind... I agree I just wanted to make sure I wad correct.

Thanks :geek:

No such thing as a stupid question, only stupid answers by stupid peeps :p

Never be afraid to ask, Hexus prides itself on n00b friendliness & friendliness in general. We have a great bunch of knowledgeable members here, all willing to help without taking the pee or flaming (mostly). :)

I do have one question though - will 2 x 4890 really be any improvement on the GTX 295 you already have (given that the 295 is basically 2 GTX 275s in crossfire, and the 275 is very similar in performance to the 4890)? Or is this for a different machine then the one in your system specs?

I take it you've seen the reviews of the 4890 2GB version? I was interested in doing exactly what you intend to do - getting a 4890 Crossfire setup running, so I've been reading up a little lately.

The 4890 with 2GB ram was shown in a couple of reviews I read to have absolutely no performance improvement over the original with 1GB ram, spare 1-2 fps at 2560x1600 with 8xAA etc in the odd game, when the framerates were unplayable anyway. Why spend the extra money - you could get a 4890 1GB crossfire setup for £250 based on that Scan offer that was up a few days ago, which is surely a heck of a lot less than this new 2GB version?

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Originally Posted by Jonessie

So in simplest terms... :stupid:

I did say it wad a stupid question mind... I agree I just wanted to make sure I wad correct.

Thanks :geek:

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No its actually a fine question, as OID correctly said there are no stupid questions :) Anyhow you would be amazed how many people would fork out a 1200watt psu for a similar spec rig because they did not ask.

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Originally Posted by scaryjim

I do have one question though - will 2 x 4890 really be any improvement on the GTX 295 you already have (given that the 295 is basically 2 GTX 275s in crossfire, and the 275 is very similar in performance to the 4890)? Or is this for a different machine then the one in your system specs?

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Forget that look at the monitor instead, he is just as bad as me. :D

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Originally Posted by shadowmaster

Forget that look at the monitor instead, he is just as bad as me. :D

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lol - I take it you've seen *my* spec ;)

The thing that doesn't get mentioned in there is that I'm currently running my newer gaming rig as an HTPC - 8800GTX powering a 1280 x 768 display :embarrassed:

AMD/ATI crossfire certified power supply list:

http://game.amd.com/us-en/crossfire_...ied.aspx?cat=3

use outervision's psu calculator (even though you probably have already).
And keep us updated if you get it done, I reckon i'll go down the path of crossfire/sli 4890/275s when I update atound crimbo :P

outervision's PSU calculator way overspecs, it sometimes reads as much as 850W for a PC a 500W PSU would run. Corsair's PSU calculator is usually pretty good.

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Originally Posted by sammorris

outervision's PSU calculator way overspecs, it sometimes reads as much as 850W for a PC a 500W PSU would run. Corsair's PSU calculator is usually pretty good.

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wow didn't know that thanks. Can be sure 750w is enough then when it read 580 for my build :)

Yeah seriously, even two overclocked 4890s and an i7 won't even use 500W.