I do have Windows 10 and OSX Yosemite in a Dual Boot setup on my editing machine (4790K, 2 GTX970, 64GB RAM) ... never been a huge fan of Windos 8(.1) - Windows 10 is awesome though. I didn't register any major performance differences between OSX and Windows but I only use Resolve for 2-3 weeks now... I can do some benchmarks if you want - and if you tell me what exactly you would need