Looking for a bit of advice on rig using older parts

Hardware Hub Build a PC
1

i have a phenom II x6 1100T 2 amd hd 6850's a hdd that i am not using i need a psu ram case and a mobo. build will be for my mom as an office desktop. and she wants to be able to mine zifter coins on it and will be doing light logo design and a lot of word doc and power point stuff as well as web page building. i am trying to keep the price in the sub 500 range.

require x16x16 crossfire support from the mobo ram 8 gigs preferred in dual channel must be 1600 psu powerfull and reliable enough for 2 hd 6850's in crossfire and a case to stuff it all in psu mounting position does not matter much but case must have decent airflow and come with 2 or more fans installed with room for a few more if needed.

parts i have found that interest me
mobo http://www.newegg.com/Product/Product.aspx?Item=N82E16813131851 ASUS M5A99FX PRO R2.0
ram http://www.newegg.com/Product/Product.aspx?Item=N82E16820148544 Crucial Ballistix Sport 8GB (2 x 4GB) 1600
psu http://www.newegg.com/Product/Product.aspx?Item=N82E16817139061 CORSAIR CSM Series CS750M 750W
case http://www.newegg.com/Product/Product.aspx?Item=N82E16811119233 Cooler Master HAF 912 RC-912-KKN1
price with parts listed $360 shipped

all input is appreciated and if i already listed what you would consider good enough let me know.

2

Does she actually need a rig with 2 6850s and all that? Also, having two x16 slots for crossfire on 6850s is not important. Those cards are slow enough that x8 (even pcie 2.0 x8) will be plenty.

3

yes she wants to gpu mine zifter coins and i have them lying around collecting dust so why not. and and x16x16 if is she ever wants to get something better.

4

Hm, if that is the case, then I would suggest getting a better power supply. It will be running 24/7, in all likelihood in that situation, so the psu needs to be reliable and efficient, likely gold rated. I would go for something from Seasonic, myself. Considering the power consumption of the cards (less than 200W each), you should be able to get by with a lower wattage psu, if you want. Keeping in mind though that a 50% load will have the best efficiency (if that 1-2% extra matters to you), and you might want to leave some headroom for future upgrades. With something like crossfire 290s being a possibility (picking up used ones later on or something), then I would look at something around 850W or higher if that is the case. Otherwise, something like 650W should be more than enough.