Eric Sauvageau discovered a very easy way to accelerate file transfer: find use sendfile = yes in SAMBA config, replace "yes" to "no", restart SMBD. My tests gives a 30% speed up while copying files from RT-N66's USB disk to Win x64 PC. Looks like a sendfile() syscall too heavy for our routers or\and it's uClibc implementation too poor. May we include this to Tomato firmware? If you wish, of course. Eric, again and again: thank you.