My quick answer is that I will stick with i7-4770k.
Here is the lengthy answer.
It is very hard to guess if I can install os x mountain lion on old generaion of xeon. I do not have such knowledge. And it is very dear to build a workstation to install xeon. You need a new set of motherboard, ram etc. It is best to buy a used xeon server vs build a new xeon workstation from cost side. But who knows if I can install os x mountain lion on that used xeon server. If I cannot install os x mountain lion, the money is wasted. I cannot afford to waste money.
If you really need speed, you should program in gpu, not cpu. There is latency of ram. You can run hundreds of threads on gpu using graphics card internal ram. You can put more graphics card in a pc to get more performance of your cuda code. I assume that you know gpu. If not, google is your best friend. FYI, I also program in CUDA.
我买了ipad air后很后悔,因为那数字触摸屏的玻璃极其的薄,非常容易碎,在美国的话就属于自己使用不当,要付US$299(买个新的机器才要四百多美元),但我认为这是DESIGN ISSUE,应该免费保修,我打算从美国买个OtterBox Defender Series Case for iPad Air保护套