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I use Ubuntu 12.04 64-bit and KVM, my CPU is Core i5 3.3 GHz and I have 8 GB of DDR3 RAM. I run Windows 7 in KVM and it's extremely slow. My co-worker use Debian on the same PC configuration and can run Windows 7 extremely fast! Where can be my problem?

sudo cat /etc/libvirt/qemu/windows.xml

OVERWRITTEN AND LOST. Changes to this xml configuration should be made using:
  virsh edit windows
or other application using the libvirt API.

<domain type='kvm'>
    <type arch='x86_64' machine='pc-1.0'>hvm</type>
    <boot dev='hd'/>
  <clock offset='localtime'/>
    <disk type='file' device='disk'>
      <driver name='qemu' type='raw'/>
      <source file='/var/lib/libvirt/images/windows.img'/>
      <target dev='hda' bus='ide'/>
      <address type='drive' controller='0' bus='0' unit='0'/>
    <controller type='ide' index='0'>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x01' function='0x1'/>
    <interface type='network'>
      <mac address='52:54:00:94:63:91'/>
      <source network='default'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/>
    <serial type='pty'>
      <target port='0'/>
    <console type='pty'>
      <target type='serial' port='0'/>
    <input type='tablet' bus='usb'/>
    <input type='mouse' bus='ps2'/>
    <graphics type='vnc' port='-1' autoport='yes'/>
    <sound model='ich6'>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x04' function='0x0'/>
      <model type='vga' vram='262144' heads='1'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x02' function='0x0'/>
    <memballoon model='virtio'>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x05' function='0x0'/>

UPD: I've enabled Intel-VT before installing KVM. I've also installed VirtIO drivers, so my Virtual Machine with Windows 7 has disk like this: screenshot of KVM virtual machines manager

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up vote 1 down vote accepted

In my little experience is better to use those settings(at least work for me)

type disk = qcow2
cache  = none
i/o mode = native

Maybe try

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Enable the Intel-VT engine in your BIOS settings.

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It was enabled before I've installed KVM. – Guy Fawkes Sep 5 '12 at 9:39
add more information about your answer or convert your answer as comment – Raja Sep 5 '12 at 17:24
I added the screenshot of Virtual Machines Manager into the question. – Guy Fawkes Sep 7 '12 at 9:57
Why was this accepted as the correct answer @GuyFawkes – WildVelociraptor Jun 16 '15 at 2:10

Change "cache" (режим временных файлов) for virtio disk1 to NONE (from default)

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