Motherboard supplies PCIe connector with power only after CMOS reset?

Hey all,

I bought a Radeon 7770 to use for Bitcoin mining, and I'm having trouble getting it powered.

First off, this is the motherboard from a Compaq Presario desktop from like 2006, it has 1 PCIe x16 slot, probably PCIe 1.0 spec, and the PSU does not have a native PCIe auxiliary power connector, the six pin one, but I have an adapter that makes one from two Molex connectors.

When it works, the 7770's fan does that boot up "turbo" and runs at a normal RPM. At this point if I unplug the six pin PCIe connector, the fan slows to a certain speed, obviously because it's not running with full power. This is how we know the six pin conector is supplying power. Now, for some reason it only supplies power some of the time, and usually I have to reset the CMOS (remove the battery) to get it the 7770's fan to run at full power (in other words, to get the six pin to supply power). I thought maybe the PSU was too weak, so I tried another one, but same issue, no change.

Just as well, nothing displays on the monitor (BIOS doesn't post) most of the time, and only does when the 7770 has all the power, but even then it's sometimes.

Come to think of it, I have a real hard time with the BIOS, sometimes, and this is before the 7770, it wouldn't post, sometimes it froze when I tried to access BIOS settings or the boot menu, and at one point it beeped obsessively if a fan wasn't plugged in, but ever since I removed the RAM from slot 1, it doesn't beep... It also beeped when RAM was in slot 1 at one point, the slot is bad or something, because the RAM in slot 2 works only in slot 2... So it's a really messed up motherboard, I'm thinking maybe the BIOS is corrupt... HP does have a BIOS update available, so I guess I'll install Windows and give it a whirl.

In the meantime, does anyone have any advice, maybe a similar experience? If anything, I want this to be on the internet so other people with this problem can see a solution (assuming I find one).
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  1. To be honest, you aren't going to mine any bitcoins at all with a single 7770. It just won't happen. You will lose more money in electricity than you will make in bitcoins.

    What PSU did you try the second time?
  2. Actually the first one was a 250w, the second a 140w... So.. But again, it works fine ater a BIOS reset, graphics, fan and all... After that, it's a toss up.
  3. you need 400w minimum to run that GPU at max load. This is your problem.
  4. But is that why it gets enough power without the CMOS battery and usually gets nothing from the PCIe power cable with the battery? I know what you're saying, I can't mine bitcoins with a 250w PSU, but I can't mine bitcoins if I can't get it to boot up either.
  5. Get a 400w or more PSU from a company like Antec, XFX, Corsair, Seasonic.

    Honestly, with a single 7770 you aren't going to mine anything. Even 4 7970's struggle now a days. GPU mining has pretty much been taken over by ASIC units. Unless you have a room full of GPU's 20-50 cards, you won't really mine much at all.
  6. I'm just going by this - , I mean the computer is on 24/7 anyway as the house server, and the calculator suggests a profit of $50 or so per month, which seems all well since the computer is on all the time anyway.

    Two months ago I would have agreed with you, but since the value of Bitcoins has tripled, ehhh I'm not so sure it's a fool's errand (without ASICs).
  7. Make sure your case has good cooling and you get a high quality PSU because this GPU will be running full speed constantly.
  8. Probably a good idea, thanks for the advice... I'm still trying to make a USB installer for Windows 7...
  9. You have to make it bootable. Then with your windows dvd, mount the ISO from the DVD to the USB stick.
  10. Well yeah, I know how to do *that* lol. Thanks again. I'll update this thread after updating the BIOS to see if that helps.
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