5.2.1 em driver and vlan issue.

I'm trying to get some stuff tested out, but I'm having a huge issue.

em0 (no ip addy)  (Intel PRO/1000)

vlan0 -> em0 (10.0.0.1/24)
vlan1 -> em0 (10.0.1.1/24)
.....
vlan9 -> em0 (10.0.9.1/24)

Everything has a MTU of 1500 (set by default)

Now, the problem I'm having is the classic, it's 'dropping' the large
packets.  Sometimes if the packet is greater than 650 bytes, sometimes 750
bytes.

I've tried setting em0's mtu to 9000 (jumbo packets, and yes, the switch
supports them), I've tried setting the mtu lower for vlan0, but nothing
seems to fix this issue.

Any idea's on how I can test this further, or fix it?  The throughput should
be sitting at port speed for my test boxes sitting on two different vlan's,
but I'm seeing speeds of around 200kbit/sec on a 100meg/sec port.  testing
between two boxes on the same vlan (so they don't route traffic to the
FreeBSD box) shows just a few kbit/sec short of 100mbit/sec.

This is starting to drive me nuts.

-Shawn