550W PSU enougth for crossfire?

[Stumps]

I posted this in the Video forums and I have been advised that asking here in the PSU forum would be a wise thing to do.

I'm looking to ditch the 2900XT I have in my rig for a Pair of Gigabyte Radeon 3870's, now that I have replaced my old GA-P35-DS3R with a GA-P35-DS3P (I got it real cheap at work).

Would my trusty Antec TPII 550W PSU be able to cope with a pair of 3870's?

It's specs are as follows

+12v1 - 19A
+12v2 - 19A
Max load 36A

+5v - 40a
+3.3v - 32a
Max load 530w (+5v, +12v, +3.3v)

the rest of my rig is in my sig.

 

[SerpentRoyal]

Should be okay. Some TP II tend to go up in flame with too much load.

 

[mpilchfamily]

The 36A that PSU would offer would be just on the edge of supporting the system. Problem is its an older PSu and may not be able to keep up with that kind of output now. Now a newer 500+W PSU will be able to handle that configuration without a problem. Take the Corsair HX520 (modular) and the VX550. both offer over 40A on the +12v rail and can easily support your system.

 

[cozumel]

You need more power imo. At least 700W PSU. Your overclocking everything and overvolting various components (more than likely). Plus waterpump etc. Haven't got a clue what expansion cards you may be using or if you have any USB/Firewire peripherals drawing power. You also have to take into account how PSU effificiency reduces with age. After about a year a typical PSU may lose about 15% in its wattage capacity and this would ageing process increases if you run your computer 24/7. In other words your trusty TPII could most likely operate at less than 500W.

Take a look at eXtreme Power Supply Calculator v2.5. You may find it useful. The lite version is free to use but the pro version will give you further amperage data.

Your PSU is the most important component in your setup. If it is underpowered and starts to fail it could take down the rest of your system. Well worth paying extra for imo.