Advice on building Litecoin mining rig

[Eiji.S]

Ok, I already have the RAM (8GB Mushkin) and a 650W Antec TruePower New PSU and a HDD.

I need to purchase a mobo, case, GPUs (2 or 3) and a CPU. If I can power 3x 7950's on the 650W Antec I already have then I'll buy 3 GPUs.

So far this is what I've picked, if you can advice better/cheaper then let me know:

AMD Sempron 145 Single-Core
http://www.amazon.co.uk/AMD-SDX145HBGMBOX-Single-Core-Efficient-Processor/dp/B0040BPHJO/

2x (or 3x) Sapphire 11196-09-40G HD7950 3GB Vapox-X Graphics Card
http://www.amazon.co.uk/Sapphire-11196-09-40G-HD7950-Vapox-X-Graphics/dp/B0091MFBZC/

Asrock Socket AM3+ 970 Extreme3
http://www.amazon.co.uk/ASRock-990FX-EXTREME3-Extreme3-Motherboard/dp/B005POPQZA/

or

AsRock 990FX Extreme3 Motherboard
http://www.amazon.co.uk/ASRock-990FX-EXTREME3-Extreme3-Motherboard/dp/B005POPQZA/

Coolermaster CM 690 II ATX Case
http://www.amazon.co.uk/dp/B005SIN99I/

[Benny1985]

There is no way you will power 3x7950s on one 650W PSU. I have 3x7950s right now, and my kill-a-watt is reporting a TDP of 760 watts between everything.

[DrG]

You can mine BTC with 3 7950s easily if can underclock the memory.  I'm mining with 2 undervolted and getting 1050MH/s at 370Watts at the wall on a 400 Bronze.

For LTC no way a 650 can handle that.  Maybe a Seasonic can run for a few days but it will die an early death.  You need a 800+

[Eiji.S]

So, would the Corsair TX850 be fine for powering 3x 7950's, even OC'd?

http://www.corsair.com/tx850w.html

Thanks!

[DrG]

That should be fine as long as you're not overvolting.  If you're going to go crazy and mine on the CPU too or put more juice on the cores or memory then maybe even a 900 may be in order.  Overvolting eats a lot more power since power is volatge squared, it's not linear.  Overclocking is more or less linear.