I have (well, had) two Fedora installation - Workstation (PC - AMD Ryzen™ 5 5600X × 12, 16GB RAM) and Silverblue (Lenovo T495, all AMD, 16 GB RAM). I’ve created Windows 10 VM in Gnome Boxes in both of machines. With same VM setup (same amount of vCPU, vRAM and storage), with guest drivers and addons installed the Windows 10 VM in Silverblue install on the laptop was so slow I could barely use it. vCPU was all the time busy 30-40% and more. I waited until updates were installed and Windows search indexing was over, but nothing changed - e.g., it still took 7-10 seconds for Firefox to start in Windows VM. Internet search didn’t help, thus I installed Fedora Workstation to my T495 as well in hope that FW is somehow technically different. And It has helped - now I can use Windows VM on the laptop normally.
I’m wondering what Silverblue specifics could result to such significant impact to Windows VM’s performance. I’d prefer Silverblue on my laptop, is there anything I could do to fix that high vCPU load ? Did you experience anything similar ? Have you fixed it ? Would you mind to share ideas/solutions ?