Quote: Originally Posted by friend863
I have ATX P4 2410A PSU. Under +12V it's written 18A. My PC is pretty old. If that helps.
The 6850 uses a single 6 pin auxiliary PCI-E power connector, so it should draw less than 150W max. According to one reference: The Truth About Graphics Power Requirements V2 - Atomic 3.0
it peaks out at 125W. That's over 10A at 12V. A PSU that delivers 18A total isn't adequate, regardless of the manufacturer's power rating.
I wish that the graphics card manufacturers would offer a little more detail about their requirements. For example, here's a "500W" PSU: Newegg.com - Diablotek DA Series PSDA500 500W ATX Power Supply
(Diablotek DA Series PSDA500, rated at 17A at +12V. Really poor.)
Here's a somewhat cheap 430W unit: Newegg.com - CORSAIR Builder Series CX430 V2 (CMPSU-430CXV2) 430W ATX12V v2.3 80 PLUS Certified Active PFC Power Supply
(Corsair CX430 V2, rated at 28A at 12V). (There's a $20 rebate available on this one, at the moment.) You might like more margin, but it'd probably be OK if you don't overclock.