OTOH if you have something like 7970,290, GTX 680,780
CPU upgrade should be a priority
What? How many games do you know where i7 4790K @ 4.6Ghz is more than 10% faster than an i7 930 @ 4.2ghz when paired with a single GPU? Unless all you do is play strategy games or MMO, there is
hardly a difference between 1st and last generation i7 @ 4.2ghz+ when paired with any single GPU card. Otherwise, you need 2 GPUs to see a noticeable difference that actually warrants a new $300 CPU + mobo. In fact, he can go ahead and get a
2nd 970 before even considering a CPU upgrade.
BFG tested a lot of games and a 4790K is barely 6% faster than a stock 2500K.
i7 930 @ 4.2Ghz is faster than a stock 2500K for gaming.
He can easily coast to Skylake. At least then he'll get all the modern features of USB 3.1, PCIe 4.0, AVX 3.2, DDR4. There is no point in upgrading to the aging Haswell architecture for him if he waited this long on an i7 930. Might as well wait 12 more months and get the latest Skylake K.