I've just bought new MBWE and see only 2.5MB/s write speed in pure 1GE LAN.
AFAIK, bottlenecks are RAM and CPU.
1. Currently installed RAM Hynix HY5DU561622E has following parameters:
DDR SDRAM 256Mb (or 32MB)
166MHz 16Mx16 FBGA (60ball) 4bank, 2.5V, CL2.5
another memory chip HY5DU121622C(L)FP-J(I) also have 166MHz FBGA (60ball) 4bank, 2.5V, CL2.5
but give us 512Mb (or 64MB). OXE810DSE memory controller support up to 64MB of 16bit RAM (according to datasheet).
It's hard to find but probably could be desoldered from some notebook SDRAM.
If you could do this then no problem with oversoldering of PCB.
2. ARM926 processor integrated in Oxford OXE810DSE chip operate at 200MHz.
OXE810DSE is obsolete. New OXE810DSE chip operate the same processor at 367MHz but with 32 Kbyte caches & MMU,
support TSO (TCP/IP segmentation offload), have 128 Kbyte on-chip SRAM, memory controller support DDR 1/2 SDRAM 16bit memory up to 256MB!
Probably old OXE chip could be also resoldier with new one, but I cannot find datasheet.
I've sniffed some flows of TCP session during write activity and discover lot of TCP retransmit.
I think network parameters of MBWE could be tuned.
Notice VIA vt6122 Gigabit Ethernet Controller support:
Jumbo frame up to 16kilobyte
Wake on LAN
802.1p, 802.1q (VLAN)
CRC offload (IPv4)