Windows 7qcow2 Best =link= -

Do not create your virtual disk using default manager settings. Default configurations use small cluster sizes that cause file fragmentation on your host storage.

What are you using? (Proxmox, pure QEMU, Unraid, or Virt-Manager?) windows 7qcow2 best

Without VirtIO, your Windows 7 VM will use slow "IDE" emulation. For the best speed: Use for the hard disk controller. Use VirtIO-Net for gigabit-speed networking. Do not create your virtual disk using default