That's true.. it would take longer for me to pay it off lol, and I think we can all agree that this is a crazy time to try out GPU mining! Well, at least I knew what I was getting into.. free electricity will help. Thanks fellas.

I recently built a rig and considering it has no hard drive or CD/DVD drive, do i really need a case at all (it seems like it just gets in the way)? If not, what should the motherboard be placed on? What about heat?

The 700 watt one had 2 rails @ 25 Amps each for a total of 50 Amps. The number of rails don't matter as long as the total is enough, right? Even so, 50 probably would't be enough. But at this point, I'm considering getting a 850-watt PSU instead. I really don't want there to be even the possibility of the thing frying my machine (esp. while I'm away).

EDIT: Can I have your opinion on this 750 watt PSU?
http://www.tigerdirect.com/applications/SearchTools/item-details.asp?EdpNo=927378&csid=_61

Yes, I understand this. I am doing this for 3 reasons:

1) Like I said, I'm a computer science major. It sounds like fun!
2) I get free electricity, so once I cover the costs of the build, its only profit (possibly)
3) I was able to find really good deals on everything.

Thank you for your concern though.

Ah, ok I'll probably get risers for the middle card and as for the power supply... sigh* I think i'll just upgrade it. I really don't want to risk it. Besides, what if i decide to overclock, that would definitely now work out. Thanks for the help, both of you!

I am new to building computers (I've always been on the software side of computer science), so I would appreciate your advice on my bitcoin mining rig. I also have a few lingering questions.

For reference, I've created a list of the components:

Motherboard: ASRock 970 Extreme4
Power Supply: OCZ ModXStream Pro Power Supply - 700-Watt??
CPU: AMD Sempron 145
Memory: Mushkin Enhanced Essentials 2GB
Video Cards: Sapphire Radeon HD 5830 (x3)??
Tower: NZXT Technologies Source 210 Computer Case
*I will be running from either a flash drive or the hard drive from my old computer

I do apologize in advance if these questions have been asked/answered already.

1) This motherboard has 3 pci-e (x16) slots, so if I use 3 graphics cards, will they fit right? Is it possible that there will be a spacial issue on the board, trying to get the cards not to run into each other, and if so, is there a fix?
2) Is a 700-watt power supply sufficient to power these graphics cards? If anyone has experience with these particular cards, your insight would be most helpful.
3) Will the mining software (I use GUIMiner) detect each graphics card separately and divide the work? I hear crossfire is not very effective.

Thanks for your help!  

EDIT: Oh, and will the traditional cooling practices work fine?