PSU and Crossfire queries

[Bearo]

Hi all,

I've recently built a new system.

intel i5 2500k @ 4.20
MSI P67-GD65-(B3)
Corsair Vengeance 1600 8GB
Sapphire HD6950 2GB
Corsair TX750 PSU
Corsair 600T Case
Corsair H60 Hydra CPU cooler
2x WD raptor 150GB on RAID 0
2x WD Cavier 1TB

My question is, when I originally looked for parts, the AMD/ATI site had information stating that the TX750 would be enough to crossfire 2 HD6950's. However, the corsair website's PSU advisor says i need a TX950...

I know i should have checked both, but the TX750 came recommended by overclockers.co.uk forums.

I would like to Crossfire my Sapphire HD6950 2GB's but don't want to find I need a new PSU especially as I've spent £80 on this TX750.

Any advice is appreciated.

B

 

[Emperus]

www.extreme.outervision.com/psucalculatorlite.jsp

Fill the above form and hit calculate to exactly know how much wattage you need. You will find out that your TX 750 has enough juice to handle your needs.

 

[user 18]

Use this PSU calculator to determine how much power you need. I'd recommend setting capacitor aging to its highest setting (50%) and looking at the recommended wattage under those settings.

http://extreme.outervision.com/psucalculatorlite.jsp

EDIT: The TX750 will handle those needs well, but once it ages, it will struggle a lot. Since you already have the PSU, it should be fine for several years, but I would prefer personally to have a higher wattage PSU to power that setup.

 

[Silvune]

Surely 50% capacitor aging is very unrealistic, especially for a high quality unit. Unless the PSU was being kept in very hot and cramped conditions, which it is unlikely to be in a 600T or in Britain.

Anyway 750W is plenty for a build with two 6950s.
http://www.guru3d.com/article/radeon-hd-6950-crossfirex-review/14
The above review shows a system with a very power hungry i7-965, which is much more power hungry than an i5-2500K, using 473 watts at the wall. Take 10 to 20% off that to take into account the efficiency of the PSU they used. 10% would be a worst case scenario, that means that their system actually drew 426W. 426 is only ~57% of a 750W PSU's capacity.
Consider that they achieved this number running Furmark, which does not place a realistic load on graphics cards, so again it is a worst case number.

Based on the above I can't see how 750W isn't more than adequate, for many, many years to come, for that build.

 

[Motopsychojdn]

+1 to Emp and User18, I actually chose the 850w to power my two 6950's,
mainly as I like overhead room to begin with, before overclocking and psu aging even enters the equation
I'd keep the 750 for now but look to building a sellon rig and putting it in there, that will fund your 850 or higher unit
Moto