I am getting very poor gaming performance on my Windows 8 host OS with Hyper-V installed but no guest machines running.
For example World of Tanks reports 60-70 FPS without Hyper-V installed and 4-14 FPS with it installed. A similar, dramatic, hit is observed in several other games so the issue is not WoT specific.
To make the point clear, I am not trying to run games in a virtual machine. I don't even have a VM running while observing this effect. I simply have the Hyper-V feature installed.
My system specs:
AMD Phenom II 965 (3.4 GHz)
AMD Radeon 6950 2GB (XFX Double D HD-695X-CDFC)
16GB DDR3 1333
AMD 790GX chipset Mainboard (Gigabyte GA-MA790GPT-UD3H)
I have tried every AMD driver from 12.8 to the current 12.11beta8, virtualization is enabled in the BIOS settings, the onboard 3300HD video device is disabled in BIOS and I have read the MSDN blog entry here regarding a similar issue in Server 2008 that was resolved in 2008 R2 (and hopefully not regressed in Win 8).
I'd like to be able to use Hyper-V for development and testing at home (I am a sysadmin/software developer professionally). If, however, I can't also use my home system for entertainment I'll have to scrap those plans.
I should note that I'm aware that Hyper-V is a Type 1 hypervisor in which the management/host OS runs within the virtualization environment. I realize that there will be at least some level of performance hit but I'd rather experience the "minimal" hit that most sources allude to rather than the "severe" hit that I'm currently able to observe and measure.