Server responding with delays on every other ping

OK, Odd one here.  I've tested extensively and have concluded that I'm baffled.  New Server 2008 R2 running on Intel hardware connected to Cisco Switches (10/100).  We are having odd communication problems (AV database replication, AD updateing, etc.) so I've done some ping testing on the server interface and get the following:

eply from 10.17.162.250: bytes=20 time<1ms TTL=128
eply from 10.17.162.250: bytes=20 time=368ms TTL=128
eply from 10.17.162.250: bytes=20 time<1ms TTL=128
eply from 10.17.162.250: bytes=20 time=355ms TTL=128
eply from 10.17.162.250: bytes=20 time<1ms TTL=128
eply from 10.17.162.250: bytes=20 time=352ms TTL=128
eply from 10.17.162.250: bytes=20 time<1ms TTL=128
eply from 10.17.162.250: bytes=20 time=348ms TTL=128
eply from 10.17.162.250: bytes=20 time<1ms TTL=128
eply from 10.17.162.250: bytes=20 time=336ms TTL=128
eply from 10.17.162.250: bytes=20 time<1ms TTL=128
eply from 10.17.162.250: bytes=20 time=353ms TTL=128
eply from 10.17.162.250: bytes=20 time<1ms TTL=128
eply from 10.17.162.250: bytes=20 time=355ms TTL=128
eply from 10.17.162.250: bytes=20 time<1ms TTL=128
eply from 10.17.162.250: bytes=20 time=351ms TTL=128
eply from 10.17.162.250: bytes=20 time<1ms TTL=128
eply from 10.17.162.250: bytes=20 time=319ms TTL=128
eply from 10.17.162.250: bytes=20 time<1ms TTL=128
eply from 10.17.162.250: bytes=20 time=397ms TTL=128

It is not constant but enough to be suspiscious.  It is apparent on traffic to this server from VPN point to point locations as well as on the LAN.  ANy ideas?

Jason