I have a pretty decent PC that I use to virtualize from time to time. I’ve used VirtualBox and it worked perfectly but I wanted to give the jump to Qemu and using KVM the difference in performance is huge but ONLY when the virtual disk is on an SSD, when is in a HDD the performance is just disgusting.
Why does this happen? I mean this didn’t happen on Virtualbox, the problem only happens in Qemu and is even funny because I have used Qemu to virtualize some distros and they run better in my laptop (with nvme) that has worse specs than my PC just because they run in an nvme and my PC on a HDD.
The hard drive is not even that old, I use it to save my games and play them from there in Linux without any problems.
Have a read of this https://serverfault.com/questions/665309/extremely-slow-disk-io-in-qemu-kvm-vm#670522