I have a i7 4790k paired up with an MSI Z97 PC Mate motherboard that only supports DDR3 memory. I plan on upgrading to the Pascal's high-end GFX when it launches, do you think my DDR3 or any other spec will bottle neck the new generation of NVIDIA's GPUs in anyway? Thanks in advance!
This is a good question, and something that's easy to answer: no, no it won't. Buy the next-gen Pascal GPU without any worries.
Done? Yeah, we are - but I'll explain a little. Your system RAM won't hold you back at all, and this would apply to both next-gen AMD and NVIDIA cards. If you had DDR2, then we might have a different answer - but that would be more because of the older CPU and motherboard you'd have, and not the DDR2 RAM itself.
DDR3 won't hold you back, and you have a pretty damn good CPU with your Core i7-4790K, too. You can rest assured, that any Pascal-based GPU from NVIDIA is going to work absolutely fine in your system, without any bottlenecking. The only bottlenecking to speak of, would be from your CPU - but there aren't many games that are CPU bound these days.