Weird problem

[Titanic3]

Dell Optiplex 380
Everything is stock except I added some new parts:
Radeon 5570
1TB Samsung HDD
750W Corsair TX750

Alright, so about a year ago, I installed a 5570 to replace the onboard G41 chipset. It ran fine up until I decided to upgrade further and bought a Radeon 6870 along with a 750W Corsair.

Here's the problem: When I plug in the 6870, the PC will not turn on (blinking orange light), so I took it out and put the 5570 back in. The PC started up normally. I took the 5570 out and put the 6870 back in again, this time, I made sure it fits into the slot perfectly, the PC turns on. I use it for hours (6+) playing games, everything ran fine. I turn the PC off, the next day, the PC won't turn on again (blinking orange light). I take the 6870 out, put the 5570 back in, the PC turns on normally. I take the 5570 out again, and put the 6870 back in, the PC turns on.

I have to repeat the cycle every time I want to turn on the PC (I'm unable to leave the PC on 24/7). It's very annoying and I don't know why. It's like I have to jumpstart the PC with the 5570 in order for the 6870 to work. I also I have to deal with conflicting drivers, some games run fine with the 6870, (Arma 2, Metro 2033, etc etc) but in some games (Guild Wars 2, BF3) I get low FPS, which I think is due to the drivers being messed up.

Any idea on how to fix it?

 

[alvine]

make sure in bios settings you have the integrated graphics disabled and set the display adapter as pcie, not onboard or auto

 

[inerax]

i have heard the dell blinking orange light is a power issue.

Kind of weird that it works with 1 card and not antoher.

What are the power connectors on both cards?

 

[Titanic3]

I have set the BIOS to use the onboard instead of "auto".

The 5570 doesn't use any power connectors. The 6870 uses 2x 6pin. I have 4x 6 pins with the 750W, I've tried all 4, the same thing happens. The 6870 works, no doubt about it. I have CCC 12.8 with it and I do see improvements in most games. Only some games (BF3, Guild Wars 2, and FSX) seems to have very minor FPS improvements or none at all. I think it's due to a driver problem, because I have to first start the PC with the 5570 installed, turn it off, then plug the 6870 in, in order to be able to use the 6870.

 

[pjmelect]

Sounds like a power supply problem, try another power supply if possible.

 

[Titanic3]

Unfortunately I only have 1 PSU good enough to power the 6870 and that's the one I'm using. I also find it hard to believe that it's the PSU because once I get the 6870 started, everything works like a charm. I've used it for 10+ hours continuously, most of that time playing intensive games and no problems were found. I still do. I just don't know why I have to "jumpstart" the PC everytime.