I have a Dell XPS 8700 with an Intel i7-4770 running Windows 7 64bit OS. Stock power source is only 460w so I was concerned with minimum power requirements for higher end GPUs. Recently picked up a EVGA nVIDIA GEFORCE GTX 750Ti 2GB GDDR5 graphics card (FTW edition) after a little research. Install was simple, but the graphics card is really long and caused me to rearrange the power source wiring a bit in order to get it to fit. Buy some small cable ties and secure any loose wiring that may be in the way. The card requires an additional 6 pin PCI-E Power cable for power. No worries, stock power source had one already and the card comes with one if you need it. Install took about 20 mins to relocate wiring and mount the card. Powered up my system and loaded the nVIDIA software with ease. I'm extremely happy with this upgrade. The card is virtually silent even under heavy load and doesn't create a lot of heat like some cards do. I use my PC a couple of hours a day and the graphics card hasn't had a single hiccup in over a year. I strongly recommend this card for anyone looking for a simple upgrade that doesn't require additional purchases (power source) for it to work.
Check nVIDIA's website for full specs on the card. Here's a couple: GPU Boost 2.0, PhysX Technology, FXAA Technology, Adaptive Vertical Sync, nVIDIA Surround, support for three CONCURRENT displays; one dual-link DVI connector, HDMI and DisplayPort 1.2, DirectX 11.2 API, 3D Vision Ready, OpenGL 4.4 Support, OpenCL Support, SHIELD Ready, G-SYNC Ready, and CUDA Technology. I run two Samsung S27C750 27" displays for my PC and have it connected via HDMI to my living room 7.2 channel A/V receiver for watching movies. The 750Ti handles 1080p 3D movie playback and the 2 computer monitors running simultaneously with ease. Picture quality and clarity on all three screens is top notch, without any degradation or pixilation issues some lesser graphics cards suffer from. I'm not much of a gamer so I couldn't say how game performance ranks but I seriously doubt this card couldn't handle most of today's popular games. Go out and buy this card, you won't be disappointed!
(P.S. This is NOT a SLI supporting graphics card. It cannot run side by side with a second GPU card for extreme gaming and processing. I would look elsewhere if that was your plan.)