Raidmax units are sketchy at best. The old saying , you get what you pay for, aptly will apply here.
The 700W unit is most likely over-rated and capable of much less stable.
personally, I wouldn't let a raidmax PSU even near a GTX GPU.
If you're stuck with it, the 2+ 6 pin is fine, you just use the 6-pin and leave the 2out. But again, highly advise going to a higher quality supply. Juice is most important in a rig.
Box 1:Xeon W3520 D0/HeatKiller 3.0/Feser Extreme 360 w/ 3x Gentle Typhoons 1850s/SWFT655/EVGA E760 Classified/ XFX GTX 285(Kool 285 block OTW)/CORSAIR CMPSU-850HX/ CM HAF /Corsair Domi's 3X2GB DDR3_2000/F1 Spinpoint 2x1TB-SATA/HT Omega Striker/ Build #2: Antec 1200/ E8500 @ 3.87 Ghz/Gigabyte P45-UD3P/ OCZ 4Gb Reapers PC2 9200/EAH4870 1GB/750W PCPC Quad Silncer/CM V10 1/2aTEC/ #3 Biostar 790GX/AMD 9950BE 3.2Ghz/OCZ Reapers 4GB 1066 /2.75Tbs of F1 Spinpoint/Corsair 550W PSU/