I don't see that, it may be time to upgrade.
I think I did figure out the problem though, I was comparing transfer logs from Smart and Flash and came across a port command difference.
Smart was sending my LAN IP 192.168.1.100 in the PORT command.
Flash I had previously set up to bind PORT commands to my WAN IP 24.86.x.x so it was sending this as the port command.
I am using a router.
The router has the 24.86.x.x address.
The XBOX is 192.168.1.200.
My PC is 192.168.1.100.
I did test this out by disabling the "bind sockets to this address" option in Flash and the transfers were about 5mb/s and it was using my LAN ip in the port command.
This not only fixed the speed problem, but files are no longer becoming corrupt either.
I switched Smart to use my 24.86.x.x for PORT commands and it too all of a sudden was transferring at about 1200k/s and was now corrupting files as well.
Now I don't exactly understand why this difference causes such a dramatic slowdown, not to mention corrupting files, perhaps you have some idea?
All the traffic is still going through the router regardless.
All I can really think of, is that the router has to match the destination MAC in the packets to route it properly and this is what causes the slowdown, and is somehow also causing this file corruption problem.
Maybe i'll contact Linksys when I get around to it ...
Quite a strange situation but i'm glad to know the cause even if I don't understand it.