(First of all: this build is more costly than a build optimized for cost vs the performance necessary to run the HTC Vive. SteamVR can run perfectly with a i5, 8GB of DDR3 ram, one inexpensive HDD, and just 350W PSU. Only the GPU is at the minimum recommended spec)
This VR-ready SFF PC is quiet.
The main OS is Linux kernel 4.4 with GNOME desktop running on the integrated GPU.
A Windows Virtual Machine with GPU passthrough ( GPU pass-through with qemu / KVM ).
The VM passes the SteamVR VR-Ready test with a mark similar to the native, bare-metal speed of this system.
The VM is used both for demanding gaming, and for asset creation with GPU accelerated sw ( without the privacy problems associated with Windows ).
The system runs perfectly the HTC Vive, but only in Windows 7 (dual-boot of the main Linux OS).
The CPU is water cooled.
The GPU is VR-Ready: at full load, the GPU makes a very audible noise but with pleasant sound characteristics.
The positive pressure of the case causes no dust accumulation.
The PSU is Corsair SFX 600W (it is new so not yet selectable in pcpartpicker).
Temperatures are OK: with Linux running the Unigine Heaven benchmark for DX11 in extreme on the Intel GPU, and, at the same time, the Windows VM running the Heaven DX11 benchmark on the other GPU at extreme, for more than one hour, temperatures never go above 80 C.
I will upgrade the GPU as soon as AMD releases its 14nm GPUs. I will also add water cooling to the GPU because the SG13 can fit two AIO radiators with one fan. That is why I chose the H75 over the H80i AIO (27 mm vs 38 mm radiator thickness).
(Minor) Problems encountered: (just so you are warned)
So far, I was not able yet to passthrough the HTC Vive to the VM (if you know how to do it, please contact me).
The motherboard does not allow to passthrough an entire USB 3 controller ( Vt-D / IOMMU / Vfio ). I tried both with ASMedia USB 3.1 controller, and with the Z170 chipset.
The HTC Vive contains about 10 USB 2.0 elements, and 2 couples of them have the same product / vendor IDs. So, until now, I was not able yet to pass-through each and all USB connections from the Linux host to the Windows guest.
The motherboard cannot run the DDR4 RAM at 3200:
2X16GB G.Skill F4-3200C14Q-64GVK
...runs only at DDR3 speed.
The AsRock web-site listed the above model of DDR4 among those able to run at full speed but, with UEFI updated at the latest version 2.1, turning on XMP causes the system to not boot. I returned the RAM and bought another, which also could not boot in XMP:
Parts purchased in April 2016.