[libvirt-users] Sluggish performance with virtio and Win10

Hello, I'm using virt-manager on my F23 box to run a Windows 10 image but the performance is so bad it's killing me. I have "vmx" flag in /proc/cpuinfo # lsmod |grep kvm kvm_intel 167936 6 kvm 503808 1 kvm_intel virtio-win-0.1.112-1.noarch But no virtio modules loaded. Should they be loaded nowadays? The disk format used is vmdk with no caching and native mode. The io is 100% in windows task manager performing less than 1MB/s Any clues? /usr/bin/qemu-system-x86_64 -machine accel=kvm -name win10-box -S -machine pc-i440fx-2.4,accel=kvm,usb=off,vmport=off -cpu SandyBridge,+osxsave,+pcid,+pdcm,+xtpr,+tm2,+est,+smx,+vmx,+ds_cpl,+monitor,+dtes64,+pbe,+tm,+ht,+ss,+acpi,+ds,+vme,hv_time,hv_relaxed,hv_vapic,hv_spinlocks=0x1fff,kvm=off -m 4096 -realtime mlock=off -smp 4,sockets=4,cores=1,threads=1 -uuid d4a67adb-5d30-42f8-b8c6-d3c4598700f2 -no-user-config -nodefaults -chardev socket,id=charmonitor,path=/var/lib/libvirt/qemu/win10-box.monitor,server,nowait -mon chardev=charmonitor,id=monitor,mode=control -rtc base=localtime,driftfix=slew -global kvm-pit.lost_tick_policy=discard -no-hpet -no-shutdown -global PIIX4_PM.disable_s3=1 -global PIIX4_PM.disable_s4=1 -boot strict=on -device ich9-usb-ehci1,id=usb,bus=pci.0,addr=0x6.0x7 -device ich9-usb-uhci1,masterbus=usb.0,firstport=0,bus=pci.0,multifunction=on,addr=0x6 -device ich9-usb-uhci2,masterbus=usb.0,firstport=2,bus=pci.0,addr=0x6.0x1 -device ich9-usb-uhci3,masterbus=usb.0,firstport=4,bus=pci.0,addr=0x6.0x2 -device ahci,id=sata0,bus=pci.0,addr=0x8 -device virtio-serial-pci,id=virtio-serial0,bus=pci.0,addr=0x5 -drive file=/usr/share/virtio-win/virtio-win.iso,if=none,id=drive-ide0-0-0,readonly=on,format=raw -device ide-cd,bus=ide.0,unit=0,drive=drive-ide0-0-0,id=ide0-0-0 -drive if=none,id=drive-ide0-0-1,readonly=on,format=raw -device ide-cd,bus=ide.0,unit=1,drive=drive-ide0-0-1,id=ide0-0-1 -drive file=/vm/storage/win10-box.img,if=none,id=drive-virtio-disk0,format=vmdk,cache=none,aio=native -device virtio-blk-pci,scsi=off,bus=pci.0,addr=0xa,drive=drive-virtio-disk0,id=virtio-disk0,bootindex=1 -netdev tap,fd=27,id=hostnet0,vhost=on,vhostfd=28 -device virtio-net-pci,netdev=hostnet0,id=net0,mac=52:54:00:cc:f0:31,bus=pci.0,addr=0x3 -chardev pty,id=charserial0 -device isa-serial,chardev=charserial0,id=serial0 -device usb-tablet,id=input0 -spice port=5900,addr=127.0.0.1,disable-ticketing,seamless-migration=on -device VGA,id=video0,vgamem_mb=16,bus=pci.0,addr=0x2 -device intel-hda,id=sound0,bus=pci.0,addr=0x4 -device hda-duplex,id=sound0-codec0,bus=sound0.0,cad=0 -device virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x7 -msg timestamp=on