nfs kernel booting is slow

[scole_mail <scole_mail%gmx.com@localhost>]

Hello,

I've got an old powermac that I boot diskless.  But when I tried to put
it on a newer and faster switch, the kernel takes forever to nfs load
and finally boot.  Once the kernel has loaded, the ethernet works fine.

If I leave the the old switch in, it works fine.

Slow kernel load:

powermac <==> 10/100/1000Mbps
nfs root      new switch

Works fine:
powermac <==> 10/100 Mbps <==> 10/100/1000Mbps
nfs root      old switch       new switch

I trying to ditch my old switch.  Both switches supposedly support
10Base-T which is what my powermac has.  I got some tcpdump and
wireshark captures for both cases, but I'm not sure what to look for.

Not Working:
08:32:03.148935 IP 10.0.0.3.1020 > 10.0.0.1.2049: NFS request xid 41 104 read fh 0,0/-293204188 1024 bytes @ 30720
08:32:03.148962 IP 10.0.0.1.2049 > 10.0.0.3.1020: NFS reply xid 41 reply ok 1124 read
08:32:05.202903 IP 10.0.0.3.1020 > 10.0.0.1.2049: NFS request xid 41 104 read fh 0,0/-293204188 1024 bytes @ 30720
08:32:05.202939 IP 10.0.0.1.2049 > 10.0.0.3.1020: NFS reply xid 41 reply ok 1124 read
08:32:05.281127 IP 10.0.0.3.1020 > 10.0.0.1.2049: NFS request xid 42 104 read fh 0,0/-293204188 1024 bytes @ 31744
08:32:05.281154 IP 10.0.0.1.2049 > 10.0.0.3.1020: NFS reply xid 42 reply ok 1124 read
08:32:07.335172 IP 10.0.0.3.1020 > 10.0.0.1.2049: NFS request xid 42 104 read fh 0,0/-293204188 1024 bytes @ 31744
08:32:07.335203 IP 10.0.0.1.2049 > 10.0.0.3.1020: NFS reply xid 42 reply ok 1124 read
08:32:07.415459 IP 10.0.0.3.1020 > 10.0.0.1.2049: NFS request xid 43 104 read fh 0,0/-293204188 1024 bytes @ 32768
08:32:07.415487 IP 10.0.0.1.2049 > 10.0.0.3.1020: NFS reply xid 43 reply ok 1124 read
08:32:09.469354 IP 10.0.0.3.1020 > 10.0.0.1.2049: NFS request xid 43 104 read fh 0,0/-293204188 1024 bytes @ 32768
08:32:09.469393 IP 10.0.0.1.2049 > 10.0.0.3.1020: NFS reply xid 43 reply ok 1124 read

Working:
08:26:21.535864 IP 10.0.0.1.2049 > 10.0.0.3.1020: NFS reply xid 46 reply ok 1124 read
08:26:21.615987 IP 10.0.0.3.1020 > 10.0.0.1.2049: NFS request xid 47 104 read fh 0,0/-293204188 1024 bytes @ 36864
08:26:21.616018 IP 10.0.0.1.2049 > 10.0.0.3.1020: NFS reply xid 47 reply ok 1124 read
08:26:23.670014 IP 10.0.0.3.1020 > 10.0.0.1.2049: NFS request xid 47 104 read fh 0,0/-293204188 1024 bytes @ 36864
08:26:23.670104 IP 10.0.0.1.2049 > 10.0.0.3.1020: NFS reply xid 47 reply ok 1124 read
08:26:23.748238 IP 10.0.0.3.1020 > 10.0.0.1.2049: NFS request xid 48 104 read fh 0,0/-293204188 1024 bytes @ 37888
08:26:23.748313 IP 10.0.0.1.2049 > 10.0.0.3.1020: NFS reply xid 48 reply ok 1124 read
08:26:25.802286 IP 10.0.0.3.1020 > 10.0.0.1.2049: NFS request xid 48 104 read fh 0,0/-293204188 1024 bytes @ 37888
08:26:25.802369 IP 10.0.0.1.2049 > 10.0.0.3.1020: NFS reply xid 48 reply ok 1124 read
08:26:25.880508 IP 10.0.0.3.1020 > 10.0.0.1.2049: NFS request xid 49 104 read fh 0,0/-293204188 1024 bytes @ 38912
08:26:25.880570 IP 10.0.0.1.2049 > 10.0.0.3.1020: NFS reply xid 49 reply ok 1124 read

Any suggestions what to look for or how to debug?  Is there something
that would need to change in the bootloader or some nfs flag?

Thanks