I am using same MCU LPC2468 with FreeRTOS in Raw mode, I get
about 2.5-3MB/s. I wrote a post on 11/22 that gave more details about my
testing/results. At these rates a lot of little factors matter. A
lot of code fine tuning, optimization. It's a lot of time consuming
testing and trial&error code rewrites. 4MB/s might be possible but
5MB/s may be optimistic, if we are talking about TCP with
full checksum and no zero copy. And that is assuming a direct
connection between lwIP and PC. 5MB/sec is approaching 50% of the full
E100 line speed. Going through a real LAN with traffic is another matter
entirely. Just going through our CISCO 2940 switches the speed takes
another hit. Increasing the zero traffic direct connection speed
beyond a certain point probably isn't going to yield much overall performance
gains when operated in a real network. Just my experience.
Chris.