bad performance with windows 2008 R2

[icoronado]

Hello!
I'm having issues with proxmox 3.1 and windows 2008 r2. When the VM is idle the cpu use is near to 0%, but when I copy files from the VM to another real host the CPU usage is about 100%. In a phisical server the cpu usage in the same scenario is near to 3-5%. If I copy files from one disk to another into the same VM the CPU usage is about 50%.

Proxmox is runing on a AMD 12 core server with 12 GB of ram. At this moment it has only one VM.

The VM has only 2GB of ram, but I can see a lot of ram free yet. The disk are RAW format in a ISCSI DELL MD3200i. All devices (disk and network) are VIRTIO with they drivers, and I have disabled ballonnig memory.

I have only 1 core in this machine, if I agree 3 core more, I can see the cpu usage going to 25-30%. This is the solution? Add more cores?

 

[icoronado]

I updated virtio drivers, install another windows 2008 R2 and windows 7 32b with the same results, I have installed the system in local disk instead ISCSI but it doesn't works.
I found another threads in the forum with similar problems and without solution. This is a common problem?