very, very slow network speed just on host but not its vm's, nothing i can figure out

[cgill]

I have a dl580 g7 with a qlogic p3 nic (nc375i)

it's network speeds within the host are slow (<5Mb/s) but networking speeds inside of its VM's are relative to the rest of the network.

this is a hyper-v host with symantec backup exec connected to a storageworks tape system via external sas connections, it does nothing else.

the host does not share the same nic port as the vm's, but they are on the same nic. when I share the nic port within hyper-v to it's host as a virtual nic, the networking speeds from the host are still slow so this leads me to believe it is a software issue on the host and not a bad nic port; however the host reports no such software issues (networking usage is very low, as is cpu and disk). hp net utility reports no errors on the nic ports, but does see that they are slow in transmission speeds <1Mbps for all nic ports (very strange to me.)

the nic is on auto-neg and each connection reports 1000-full. they are connected to a procurve 4108gl which connects to a 5406zl. I have updated the nic drivers.

i have run iperf with the duplex command to help diagnose this issue and inside the vm's they report full duplex speeds in relation to the network (which is still rather slow around 100Mbps) but on the host it reports one half of the connection as ~5Mbps and the other half as ~100Mbps; this alternates back and forth but one-half is always a 10th of the speed on the host no matter if it's a virtual nic of the VM's nic port or it's the other nic that is designated for the host.

if you have read this far, wait for this peculiar occurance: if I disable the nic ports that lead to the procurve, the tranmission speeds on the remaining nic ports are full duplex and fast. NIC port #3 goes to a separate netgear switch with some servers i have on there. but once i enable either nic #1 or #2 ports, nic port #3 along with any other nic port is slow again. this is the baffling portion, as it leads me to believe it is the procurve switch causing the issue.

this is why i am banging my head against the wall, if anyone has any ideas to this situation please chime in :) 

by the way the vm's on the host are using the exact same edition of windows server (2008 r2 64bit)