Can I maximise performance of 2 cards?

Computer Type: PC/Desktop
System Manufacturer/Model Number: Self Built Custom
OS: Windows 7 Ultimate Retail Box (64-bit installed) + Service Pack 1
CPU: AMD FX-8350 CPU v1.15 (or 1.0F) BIOS was required!
Motherboard: MSI 890FXA-GD70
Memory: 8G CAS-7 G-Skill DDR3 @1333 (2 fours) [mobo nonOC max rec'd]
Graphics Card: Radeon HD 7950 [3 gigs of GDDR5] MSI Twin Frozr model
Sound Card: Realtek High Definition Audio (onboard mobo, ALC-889 chip)
Monitor(s) Displays: 2 WS LED Monitors: One LG One Viewsonic
Screen Resolution: 1920 by 1080
Keyboard: Logitech G11
Mouse: Logitech M310 Wireless
PSU: Corsair TX850 - 850W max, in service since August 2010.
Case: Thermaltake Armor A90
Cooling: Thermaltake Spin Q CPU Cooler, in service since August 2010
Hard Drives: SSD for OS: Samsung 840 Pro SSD for VM and utilities: Adata SX900 7200 RPM SATA HDs for the rest: Hitachi and Seagate
Internet Speed: 100 Megabit broadband supposedly upgraded from 50 (Cable)
Browser: Pale Moon 64-bit main, also IceDragon, Opera, and Maxthon.
Antivirus: Bitdefender Internet Security 2014 suite
Other Info: CompTIA A+ certified (220-800 series) in July 2013.