I've got about $500 to spend on an upgrade on my current rig. I'm running an i7 950 on a sabertooth x58 board with 2 gtx 570s and an 840evo ssd. I'm thinking either a CPU and motherboard update (4770k and sabertooth z87 or equivalent) or going graphics and getting a gtx 780. The Haswell refresh is right around the corner and the 800 series is questionable timeline wise as far as I know. What am I going to get the biggest benefit from in terms of overall use. I do a lot of video encoding (handbrake) so the i7 is desired and I feel like the x58 chipset is dated. On the same hand, I'd like to have the 780 for gaming but my 570s are doing alright for me with everything I've been playing so I think my motherboard chipset is the limiting factor for me right now, any arguments?