It's time for me to upgrade my external graphics card on one of my PC's (Intel Core i7 3770 | 32GB (4 x 8GB) Kingston Hyper X DDR 3 1600 XMP | eVGA GeForce GTX 750 Ti | ASUS P8Z77 V LE PLUS) to pump out more pixels (GP/s), and textures (GT/s). The only limitation I have is size. The case I'm using is a "Cooler Master 311 Elite" I only have room for a 9 1/2 to 10 inch graphics card, max, before I start to run into trouble. However I want a top-of-the-tier GPU with as much GDDR5 as possible. Which are the most powerful cards I can choose between to stuff in a limited (i.e. confined) space?