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

[Jonessie]

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)

[DDY]

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.

[shadowmaster]

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

[Jonessie]

So in simplest terms...

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

Thanks

[0iD]

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

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).

[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?

[jim]

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?

[shadowmaster]

So in simplest terms...

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

Thanks

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.

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?

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

[scaryjim]

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

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

[gingerBen]

AMD/ATI crossfire certified power supply list:

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

[nibbler]

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

[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.

[nibbler]

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.

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

[sammorris]

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