I7 4790K Has very good single thread performance because of the high stock Clock.i7 4790k can easily overclock to 4.6-4.7 with much little effort from a novice overclocker like myself.,you can even get good single thread performance from Sandy Bridge/haswell/broadwell/skylake CPU's by just overclocking them yourself.
as for VR i think getting a good processor like i7 4790k/i7 6700k/i7 5820k would be a smart choice ideally i7 4790k or i7 6700k if you dont wish to buy a AIO cooler for i7 5820k(getting high overclocks req better cooling).,i would still get a quiet aftermarket cooler for the 4790k/6700k though.
personally i say get the best Graphics card you can get and then the best CPU you can afford with your budget,I love my i7 4790k but being stuck with a cheap r9 280 3gb card makes me feel sad since VR reqs gtx970/390....But i can just upgrade later which is the benefit of PC Master Race
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