Re: Mixed vender SLI
I don't think it will make any difference as long as the clocks and memory type are the same. Everything else is probably reference design except for the heatsink perhaps.
Basically if you overclock both your gpu/mem with coolbits, they should be running the same clocks.
Not sure about your scores though. 3Dmark05 seems low, but that may be because of your CPU. 3dmark05 is very CPU dependent so I hear, and you seem to be running your processor at stock speeds.
My pimp'n rig
Athlon64 Venice 3000+ @ 2.6GHz (4100+) · Win XP Pro x86, Vista Ultimate x64 · eVGA K8-NF41 nForce4 SLi · Corsair XMS 1.5GB PC3200 CAS2/1T · eVGA 2x 6600GT SLi · Leadtek Winfast TV2000 XP Deluxe · Western Digital Caviar SE ½TB RAID 0/1 · PowerLink LPK2-30 400W · LiteON LDW-411S OC to 811S 8x DVD±R/RW/ROM · MicroAdvantage 64MB QuickiDrive · Samsung SyncMaster 931B 19" LCD · Microsoft Optical Wheel Mouse USB · Sony PSXtoUSB Analog Gamepads · Memorex MX2700 Multimedia Keyboard · Lexmark 3200 Color Jetprinter · nForce Network Controller 1Gb/s LAN (Cable ~3Mb/s down) · ΩPioneer Dolby Digital 5.1 Surround Sound