I have a 600W PSU, but it’s a couple years old so it only has two 6 pin connectors. The eVGA card I got came with both
6+6 -> 8 and molex+molex -> 6
adapters. Unhappily, I crossed my fingers and tried it, and all was well.
On newegg.com, look at the PICTURES of the cards, which have a shot of the included cables and such, you can see which brands include adapters and which ones. I picked the eVGA mostly because I knew ahead of time I was in a PSU grey zone, my gamble worked.
I’m disappointed in the eVGA card, though, it proudly talks about thier GX 280 color power LED for diagnosing any power problems… the GX 260 does not have it. Except when I got my card… the GX 280 doesn’t have it either. Sigh. I’d love it if board level probes could tell you voltage/amps being delivered by each connector.
Since my board is running CUDA programs for over 24 hours straight, I suspect my power will be fine.
Back to the topic of futureproofing your development platform:
Get a motherboard with TWO x16 PCI-E slots with DOUBLE SPACING. Even though you’ll get just one card now, and only need one slot with double spacing. It will be very tempting later to pop in a second card, and if your motherboard can’t fit it, it will cramp your options considerably.
Look for one with TRIPLE double-spaced slots for even more flexibility.
There is at least one known MB with quad double-space slots, but that may be one-of-a-kind.
And get 4GB of RAM at least, and use a 64 bit OS (Linux preferred, but XP is OK), and a quadcore CPU.