not effective fscache with nfs store

system: proxmox 2.2
storage: freenas 8.3
guest hdd mode: nocache

i install the fscache with apt-get install cachefilesd
the document i followed: http://www.cyberciti.biz/faq/centos-...ilesd-for-nfs/

all are no problem
the second copy from nfs server is very fast in linux console (already clean the system read cache)
but in the guest windows 2003, the fscache is not effective

can anyone tell me why ? is it need to use nfs v4 ?