A couple years ago I tried out Vray RT but didn't have a lot of success as it had limited features and I assumed my old graphics card (GTX 580 3gb) wasn't up for the job. Today I finally updated to Vray 3.4 and thought I'd give RT another shot and I must say I'm amazed with the results. My crusty old GTX 580 is double the speed of my i7 3930k (6core CPU OC @ 4.1GHZ). My CPU is a few years old now but is still holds it's own against the new CPUs when it comes to bang for buck for rendering. Although the 3gb of GPU memory will be limiting in some scenes, these tests are making me rethink if I should update my entire system or just buy some new graphics cards. Latest gen GPUs CUDA core count is about 5x more than my card so I can only assume the render times could many times faster than my card. Some benchmarks are shown below.