Crossfire HD5850s wise with 650W PSU?

[mof]

My computer has the following:

AMD PhenomII x6 1090t @3.2 GHz
HD5850
2x2GB DDR3 RAM (Corsair xms3 1333MHz)
Gigabyte 890fxa ud5 motherboard
Hitachi Deskstar 3TB 7K3000 SATA III Hard Drive
Corsair TX650W psu http://www.corsair.com/tx650w.html
Max Load: +3.3v=24A, +5V=30A, +12V=52A, -12V=.8A, +5VSB=3A
(I've had it just over a year).
I've been thinking about getting another 5850. Probably before bf3 comes out.
According to this site
http://extreme.outervision.com/PSUEngine

if I had 2 5850s my minimum psu wattage would be 555 W and my recommended psu wattage would be 605W. This includes 20% capacitor ageing.
However on corsairs psu calculator they recommend a 750W psu for the dual card setup.

Would it be safe to get another gpu with my current psu? How serious would the risk of damage to the components be?
I'd prefer not to spend money on psu when it could go towards a new graphics card.

Also is £130 the best price I'm likely to get for a 5850?
I've been checking the 'today only' deals and I assume I'll be able to get one for about £100 if I wait for a while. I want to get one before BF3 but it wouldn't hurt to get one now.

Any advice would be appreciated.

 

[Surveyor]

Hi and welcome to the forum.

It might be touch and go with that PSU.

Guru3D recommend 55-60A on the 12V rail:

Radeon HD 5850 review (CrossfireX) Power Consumption

You'd also need to use molex adapters as the PSU only has 2 PCI-E power connectors and you'd need 4.

Your guess is as good as anyone elses on the price. The HD 5850 is an older card but still popular as it perform quite well compared to the newer cards.

Prices could go the way of the GTX 480. Not so long ago they were being sold at £200 to get rid of large stocks. Now there aren't many left they're over £300.

 

[mof]

Thanks Surveyor, I didn't even know about needing the molex adaptors.
That link is very helpful and it does look very borderline.
I'm not sure what I'll do now. It seems like a bit of a waste to replace the psu already and I don't suppose I'd get much from selling it.

 

[Tokin]

Hi and welcome to the forum.

It might be touch and go with that PSU.

Guru3D recommend 55-60A on the 12V rail:

Radeon HD 5850 review (CrossfireX) Power Consumption

You'd also need to use molex adapters as the PSU only has 2 PCI-E power connectors and you'd need 4.

Your guess is as good as anyone elses on the price. The HD 5850 is an older card but still popular as it perform quite well compared to the newer cards.

Prices could go the way of the GTX 480. Not so long ago they were being sold at £200 to get rid of large stocks. Now there aren't many left they're over £300.

You can still get 480's for 200 mate

 

[Surveyor]

You can still get 480's for 200 mate

Well mate, when I made that post OcUK were selling retail GTX 480's with a full warranty at over £300 and they still are.

As this is is OcUK's forum we're not allowed to discuss competitor prices.