Im looking at perhaps getting the HD 3870 X2 video card. I currently have an nvidia 8800GT 512mb. My motherboard is an Intel 38DX so I cant SLI 8800s on it so hence im thinking of 3870x2. I could possibly switch to an nvidia 790i motherboard coming out soon and a 2nd 8800GT 512 and SLI those for about the cost of the HD 3870x2 although it would require more work since I have to swap the motherboards and the CPU,RAM etc and I dont think it is worth it.
power supply and it has come to my attention that it is not so great although its specifications looked good to me when I bought it.
Will this PSU be able to handle the HD 3870x2? It has 2x PCI-E 6 pin connectors. If it can handle it at stock speed, could it handle overclocks onthe HD3870x2? I dont think it will and hence I would have to buy yet another PSU that is certified for Xfire/SLI for real this time and stop playing around with these low cost yet misleading PSUs.
While your PSU may very well be able to handle the HD3870, I doubt its longevity will be great. Ultra PSU's are VERY shoddy. The additional strain put on it by the X2 will probably only cause it to die (and plausibly take out other components), that much faster. It would probably handle an overclock just as well, but the fact remains that its going to die regardless of whats stressing it. Ultra PSUs are very saggy as is, and fluctuate horribly. They are also greatly overrated, but id say the 750w rating is more like a 500w PSU (but thats still enough to handle the X2).
So the short answer is yes it will work, for a while anyway. I still recommend you get another power supply
I recommend an Antec TPQ 850 or 1000 if you plan on going CrossfireX in the future with two 3870x2's or similiar 4xxx series cards.
I had to go Antec Neo 650 for budget reasons. That supports just one 3870x2. Here's ATI's certified PSU list. Some Ultras are on it, but most PSU's by that company aren't all that good. It probably depends on who they subcontract out to build the PSU. I looked for yours on the certified list of Ultra PSUs for a single 3870x2, it's not on the list.