tx v2 error 0x6204<UNDERFLOW> - is this a new feature?

[fbsdmail at dnswatch.com]

Greetings,
 I have been receiving these messages on a recent 8.1/AMD64 install.
src/ports && world/kern about a week ago. Here is a block from the most
recent output:
nfe0: tx v2 error 0x6204<UNDERFLOW>
nfe0: tx v2 error 0x6204<UNDERFLOW>
nfe0: tx v2 error 0x6204<UNDERFLOW>
nfe0: tx v2 error 0x6204<UNDERFLOW>
nfe0: tx v2 error 0x6204<UNDERFLOW>
nfe0: tx v2 error 0x6204<UNDERFLOW>
nfe0: tx v2 error 0x6204<UNDERFLOW>
nfe0: tx v2 error 0x6204<UNDERFLOW>
nfe0: tx v2 error 0x6204<UNDERFLOW>
nfe0: tx v2 error 0x6204<UNDERFLOW>
nfe0: tx v2 error 0x6204<UNDERFLOW>
nfe0: tx v2 error 0x6204<UNDERFLOW>
nfe0: tx v2 error 0x6204<UNDERFLOW>
nfe0: tx v2 error 0x6204<UNDERFLOW>
nfe0: tx v2 error 0x6204<UNDERFLOW>
nfe0: tx v2 error 0x6204<UNDERFLOW>
nfe0: tx v2 error 0x6204<UNDERFLOW>
nfe0: tx v2 error 0x6204<UNDERFLOW>
nfe0: tx v2 error 0x6204<UNDERFLOW>
nfe0: tx v2 error 0x6204<UNDERFLOW>
nfe0: tx v2 error 0x6204<UNDERFLOW>
nfe0: tx v2 error 0x6204<UNDERFLOW>
nfe0: tx v2 error 0x6204<UNDERFLOW>
nfe0: tx v2 error 0x6204<UNDERFLOW>
nfe0: tx v2 error 0x6204<UNDERFLOW>
nfe0: tx v2 error 0x6204<UNDERFLOW>
nfe0: tx v2 error 0x6204<UNDERFLOW>
nfe0: tx v2 error 0x6204<UNDERFLOW>
nfe0: tx v2 error 0x6204<UNDERFLOW>
nfe0: tx v2 error 0x6204<UNDERFLOW>
nfe0: tx v2 error 0x6204<UNDERFLOW>
nfe0: tx v2 error 0x6204<UNDERFLOW>
nfe0: tx v2 error 0x6204<UNDERFLOW>
nfe0: tx v2 error 0x6204<UNDERFLOW>
nfe0: tx v2 error 0x6204<UNDERFLOW>
nfe0: tx v2 error 0x6204<UNDERFLOW>
nfe0: tx v2 error 0x6204<UNDERFLOW>
nfe0: tx v2 error 0x6204<UNDERFLOW>
nfe0: tx v2 error 0x6204<UNDERFLOW>
nfe0: tx v2 error 0x6204<UNDERFLOW>
nfe0: tx v2 error 0x6204<UNDERFLOW>
nfe0: tx v2 error 0x6204<UNDERFLOW>
nfe0: tx v2 error 0x6204<UNDERFLOW>
nfe0: tx v2 error 0x6204<UNDERFLOW>
nfe0: tx v2 error 0x6204<UNDERFLOW>
nfe0: tx v2 error 0x6204<UNDERFLOW>
nfe0: tx v2 error 0x6204<UNDERFLOW>
nfe0: tx v2 error 0x6204<UNDERFLOW>
nfe0: tx v2 error 0x6204<UNDERFLOW>
nfe0: tx v2 error 0x6204<UNDERFLOW>
nfe0: tx v2 error 0x6204<UNDERFLOW>
nfe0: tx v2 error 0x6204<UNDERFLOW>
nfe0: tx v2 error 0x6204<UNDERFLOW>
nfe0: tx v2 error 0x6204<UNDERFLOW>
nfe0: tx v2 error 0x6204<UNDERFLOW>
nfe0: tx v2 error 0x6204<UNDERFLOW>
nfe0: tx v2 error 0x6204<UNDERFLOW>
nfe0: tx v2 error 0x6204<UNDERFLOW>
nfe0: tx v2 error 0x6204<UNDERFLOW>
nfe0: tx v2 error 0x6204<UNDERFLOW>
nfe0: tx v2 error 0x6204<UNDERFLOW>
nfe0: tx v2 error 0x6204<UNDERFLOW>
nfe0: tx v2 error 0x6204<UNDERFLOW>
nfe0: tx v2 error 0x6204<UNDERFLOW>
nfe0: tx v2 error 0x6204<UNDERFLOW>
nfe0: tx v2 error 0x6204<UNDERFLOW>
nfe0: tx v2 error 0x6204<UNDERFLOW>
nfe0: tx v2 error 0x6204<UNDERFLOW>
nfe0: tx v2 error 0x6204<UNDERFLOW>
nfe0: tx v2 error 0x6204<UNDERFLOW>
nfe0: tx v2 error 0x6204<UNDERFLOW>
nfe0: tx v2 error 0x6204<UNDERFLOW>

It appears to only occur when transmitting largish amounts of data
across an NFS mount. I'm not sure where the MIN-threshold lies. But
appears to be >=1.5Mb.
This fresh 8.1/AMD64 is part of a largish server farm comprised of
7+ - 8.0 i386 servers. This one is the only AMD64. It is also the
only AMD64. I experience this when mounting an 8.0/i386 server from
this 8.1/AMD64. The i386 also has mounts on this 8.1/AMD64.
relevant info:
### 8.0/i386
8.0-STABLE FreeBSD 8.0-STABLE #0: /usr/obj/usr/src/sys/UDNS01  i386
Tyan 2-CPU MB
2 NIC's: fxp0 (only one in use)
### 8.1/AMD64
FreeBSD 8.1-RELEASE-p2 #0: /usr/obj/usr/src/sys/XII amd64
MSI K9N4 Ultra
CPU: AMD Athlon(tm) 64 X2 Dual Core Processor 4200+ (3511.34-MHz K8-class
CPU)
1 NIC nfe0
### common to both:
rc.conf
nfs_client_enable="YES"
nfs_reserved_port_only="YES"
nfs_server_enable="YES"

NIC's on both boards are 10/100's @100mbps

Can anyone provide any insight as to why I should be receiving these
messages on a fresh 8.1/amd64 install. Is 8.1 INcompatible with
earlier versions?

Thank you for all your time and consideration.

--Chris