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Weird performance issues

Hey all, I have a win10 GPU passthrough setup with weird performance issues.
I think it is probably a VirtIO isseu. The symptoms are:
Secondary HDD disapearing randomly, windows (sometimes) prompting I reformat it.
I tried this but explorer becomes completely unresponsive

Before I was able to copy a couple of things to it after like half a hour it comes up with a IO error.
The boot drive has similar issues but is always able to boot but it most of the times it takes more than 15 minutes even tough the boot drive is mounted on a NVME SSD.
I have both set to VirtIO with all the hypervisor defaults.
I figured out pretty early I couldn’t enable the writeback option because my NVME SSD (linux boot drive) is fully encrypted. However I tried to enable this for the HDD and it made no difference.
Tonight I tried to extract a 14 GB zip file to my desktop it’s source was also the boot drive. When I woke up it was stuck halfway trough the copying of the files.
Because of all these issues I have not been able to properly debug this because I wouldn’t know how to describe these issues to a search engine.
As for my GPU passthrough its working wonderful. I was able to install heaven benchmark and it works like I would expect.

I hope you all would be able to help me de-bug this so I can use my machine to its full potential again.
Specs:

CPU: Ryzen 1700X @3.3GHZ (host-passthrough disabled hyper-threading for debugging)
Passed through GPU: Asus Nvidia 1060 OC 6GB
Linux GPU: Advanced Micro Devices, Inc. [AMD/ATI] Pitcairn PRO [Radeon HD 7850 / R7 265 / R9 270 1024SP]
Linux distro: Arch linux
HDD:ATA ST3000DM008-2DM1
For the NVME drive I couldn’t find specs from within my linux machine but I have no problems on linux where copying files is slow, the speeds should be more than 1000MB/s write and read.

XML from within virt-manager/qemu:
https://pastebin.com/raw/7b2Mhiv3

If you have any questions let me know i’ll try to respond asap

hi, could you create a second VM as a “pc-i440fx-4.2” machine and create 2 new vdisks and test again.
Is there a reason your win10 drive is a qcow2 disk?