In terms of performance you can be sure that a build with i7 and descent graphics is going to be faster.
But I'm not sure if a Hackintosh is a good server...
I personally use an older Mac mini as a media server and do my photo editing on my Hackintosh (i5 3470k and GTX 660).
I've got a problem with ethernet!
I installed the Lnx2Mac driver
If I put in the ethernet cable, istat shoes activity but with download speed of 0.0 KB/s
I also deleted the Realtek kext and installed it again but ther is the same problem again!
I've got internet connection using...
I need an antenna because there is no USB cable with is long enough to get to the point with minimum 350 kb/s (with actually isn't that fast) so I need an antenna.
And that's why I boot an Edimax USB Stick with antenna connector!
When it arrives I post if it works or not
I don't know which PCI wifi card I'm able to use!
I need it because in my room I haven't ethernet or good wifi so I putted a antenna on my old PowerMac in front of my door!
Now I've builded a hackintosh and want to use the antenna again.
Or do you know other ways to get good...