For better PCI Express support and performance, use q35 instead of the older i440fx when creating your VM.
To close the performance gap with raw disks, use these specific optimizations during image creation and VM setup: 1. Optimize Cluster Size
QCOW2 is often preferred over raw images ( .img or .raw ) for Windows 7 VMs due to several key features: windows 7qcow2 best
virsh snapshot-create-as win7-vm baseline --disk-only --atomic
Test environment:
Use qemu-img convert to compress or compact your image over time to keep it running at maximum speed.
When setting up a virtual disk in QEMU/KVM, you generally choose between and QCOW2 . While Raw files offer a microscopic edge in raw read/write speeds, QCOW2 is overwhelmingly the best choice for Windows 7 due to its advanced feature set: For better PCI Express support and performance, use
To maintain the best performance, you will need to manage the qcow2 image over time. Converting Existing Disk to QCOW2
To achieve the absolute best Windows 7 QCOW2 setup, your final architecture should look like this: Optimal Setting QCOW2 with preallocation=metadata Storage Driver VirtIO Block / VirtIO SCSI ( viostor ) Host Cache Mode cache=none (for SSDs) CPU Type host passthrough Display Protocol QXL video driver with SPICE guest tools VirtIO Version Build 0.1.173 or 0.1.185 (Legacy Signed) When setting up a virtual disk in QEMU/KVM,