different disk sizes

[ds(ds)]

1)in proxmox 3.1 create qcow2: {ide-32gb (os:win2003; free 27gb; use:7gb)} output= wma.gz 2.25 gb
qemu-img info (virtual size:32 gb, disk size:5.3gb)

2)restore in proxmox 3.1 from backup proxmox 1.8 (qcow2)
{ide-32gb (os:win2003: free 23gb; use:8gb)} output= wma.gz 7.60 gb
qemu-img info (virtual size:32 gb, disk size:14gb)

Why do different disk sizes, if busy place almost the same?


(sorry for my english)