Comp keeps restarting

[kil_bot]

hey i just built a computer. first one i built.

CPU:intel Q9400
MB: Asus rampage formula
Ram: gskill 4 gb 1066
GPU: gigabyte HD 4670 512mb
PSU: mod Xstream Pro 600w

ran great nice and cool, but then i took out the gigabyte HD4670 and put in a ATI HD 4870 1gb, tryed to boot it up, and it started to go for about 20 seconds showed the initial start up screen then shut off....and then kept
starting for 1 second and shutting down..and over and over...if any one has any ideas thanks.

 

[boudy]

It kind of sounds like the power supply, but your's is pretty good...
You say that you "took out the gigabyte HD4670 and put in a ATI HD 4870 1gb", you don't mean literally do you?

 

[jaguarskx]

Did you connect the two 6-pin power connectors to the HD 4870?

 

[jsc]

jaguarskx,

... and it started to go for about 20 seconds showed the initial start up screen then shut off...

First thing to do is to put the old card back in. Does the system still work?

If so, your problem is either the power supply or the new video card. And it seems unlikely to be the PSU. A 4670 needs about 6 amps. A 4870 needs about 11 amps and your PSU is certainly more than adequate - if properly functioning - at those power levels.

 

[kil_bot]

yah i put the old card back in...works fine again...is there a way to test my power supply?