Hi Bent,
Have you tried the latest bz321111 kernel from Johnny?
<http://people.centos.org/hughesjr/kernel/5/>
I have kind of lost faith in RH kernels as far as NFS performance is
concerned - and yes, I know that the bz321111 issue is supposedly
solved in 5.2 but until we can positively confirm that ourselves I
ain't letting it near our production servers