Yep,tried them on DFI nf4 sli dr, sli dr expert and gigabyte ga-k8nf-9-rh with 6-7 cpus on socket 939,with p4p800,p4c800 (x2),ic7,8pe800,865pe neo2 with ~50 cpu on socket 478.
Also tried on a couple of nf2 (462) board and a bounch of processor.In no case were able to boot with cas >2.
Other random memory works fine with any cas in all the mobos so, yes, i'm pretty sure it is a memory issue.