The computer is an eMachines EL1331G-05w which has the AMD Athlon II X2 235e processor, 6GB of memory, a 750GB hard drive, and measly 6150SE graphics.
I will be placing a 700 watt PSU and my wife's old HD4870 512MB video card in there.
First of all, will the ATI card even run if there is an nVidia graphics set on the board? I assume I can disable the on-board graphics in the BIOS, but is my assumption correct?
Second, in the future, I may wish to swap out the processor for a II X4 600e or 605e (whatever I can get cheaper on eBay). Will that processor work with this computer? Has anyone upgraded a EL1331G to a better energy efficient AMD chip?
And finally, this motherboard is supposed to have two PCIe 2.0 slots. If I throw in another HD4870 card, will a 700 watt PSU be enough? How about with the faster CPU as well?
For the record this is probably one of the ones that's really just a AM2 motherboard. I have one myself, and it says on its specs page that it will support AM3 CPU's but it also says that the bus speed will be majorly reduced.
Personally I wouldn't want to run an AM3 CPU on such a thing. I am aware that money is likely an issue, but you could sell that CPU/mobo on ebay, make somewhere between $60-100 (depending) on it then get a 770 chipset or higher AM2+ mobo and a better CPU. Maybe one of the tri-cores. (oh and for crossfire it would have to be higher, and if that motherboard you have really is one of the ones I think it is, it only has one. If it does have two then it's nvidia so it would only support sli.) Then you could reuse your RAM, and be setup for for multiple crossfire cards.
Why one of the energy efficient ones? Those're expensive because they just test better at lower voltages, and don't even make that much of an energy use difference.