I currently own a server which runs a couple of virtual machines (FreeBSD for ZFS storage, and a couple of Linux based machines for e-mail, dns, home automation, ... ), nothing too fancy. It is equipped with an Intel Core i7 3770, 32GB of RAM, SSD for OS, 5x 2TB HDD connected to RAID controller (linked to my FreeBSD machine using vt-d), Gigabyte Z77x-DH3 and high performance PSU.
I ordered a Sapphire HD7870 2GB GPU and want to use the server for mediacentre and gaming. I'm not worried for media, but I'm wondering if I'll be able to use the machine for normal-to-high end gaming.
I know the limitations of a HD7870, meaning I will not be able to play games like Crysis 3 with max settings on 1080p.
My question is: will the virtual machines affect my gaming performance? My machine uses about 25% CPU and about 20-22 GB of memory. my RAID controller used an x16 PCIx lane at x8 speed. The GPU will thus only be able to run x8 speeds, because of bandwidth limitations. Will this affect performance? Will switching to socket 2011 and six-core i7 speed up my system?