I right now own a 4GB GTX 680 and can sell it an buy a GTX Titan SC edition. I won't consider that GTX 780 because I'd be going from 4GB down to 3GB. I would have considered the GTX 780 SC edition but I don't want to downgrade to a 3GB video card. I can afford a GTX Titan SC edition. I prefer single GPU systems (less issues and less troubleshooting than SLI), so no SLI more me. Would it be worth it going from a GTX 680 to a GTX Titan SC?