I just put together a system using an ATI 4870x2 and a Coolmax 650w PSU.
My issue is that the power supply has 2 2x3 PCIE power plugs, and the
graphics card needs a 2x3 and a 2x4. I've found all kinds of adapters for
getting a 2x4 from 2 molex plugs, or a straight 2x3 to 2x4 adapter, but I've
also seen comments in forums that using the adapters can leave the video
card underpowered depending on the PSU setup.
I'm not trying to overclock anything at the moment (and I don't really think
I will be in the future either), I just want to get the machine working. My
question is if I hook up the 2x4 from the 2x3 with an adapter will it work?
You would be right in that it's not necessarily an Ideal solution, and that depending on the quality of the PSU, you might be underpowering your cards (which in your case, you should be OK as the PSU meets minimum standards from ATI's web site). However, you should be fine via a double molex or 6 pin --> 8 pin converter.