unRAID 6.6.6 - Slow Disk Performance in Windows 10 VM


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Alright I've been racking my head against the wall with this for about 2 weeks now so maybe someone can help.

 

I have a Windows 10 VM with an NVME disk passthrough. If I benchmark the disk in CrystalDiskMark, it gets about 20% of the performance in all categories that the same disk gets running Windows natively on the machine. I've tried several other benchmarking tools and they all give the same result, performance is significantly worse than running on the system itself. I've tried multiple things to get the speeds to improve but so far nothing's worked. Some of the things I tried:

 

Tried another SATA SSD and got the same speeds

Tried using a vDISK on the cache drive and got the same speeds

Tried both VirtIO and SATA as the vDisk bus

Tried both SeaBIOS and OVMF
Tried multiple combinations of CPU and RAM in case it was just a bad configuration on my part

Installed the unassigned devices plugin in case that made a difference
 

Regardless of which SSD I am using, or the VM configuration, the disk performance is still significantly slower than running on the machine directly. I attached my diagnostics in case someone wants to take a look. Any advice is appreciated.

sirius-diagnostics-20190202-1744.zip

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