That should be more than enough for the CPU and GFX card. Yes I think it's GFX related, would be most interesting to test with a different 4870 or a GTX285/GTX275 which all require similar power, but maybe not so much peak.

More information. My 4870 got the 3 red lights:

D1601 - Red LED On, shows critical temperature fault

D1602 - Red LED On, shows External power connector A was removed

D1603 - Red LED On, shows External power connector B was removed

D601 - Red LED On, shows critical Core power fault


On my 4870, D1602, D1601, D1603 are on after power up.

Update:

So I ordered a PSU (TX750) because it only takes a week for a new PSU to come and RMA videocard takes at least 2 weeks.

While I was waiting for the new PSU to come, I removed the 4870 and leave only 1 stick of ram and used the onboard video again. I got the same no post problem. And the problem is getting more random (sometimes it took many trials to boot to window.)

New PSU came today and after I installed the new PSU. I got the same problem. Onboard video only with no post. However, the few times I tried, I can start the computer at 2nd trial. Sometimes, if I got no post, I got 1 long beep and 2 short beeps, I googled and it seems to be video problem.

It seems like I have a motherboard problem