rsync synchronizes VERY slow

[Zoltan HERPAI]

hi,

I have an 20G archive of pic files which would have to be mirrored onto
another server. It contains large JPEGs, around 10k files, one of the
servers is located in Boston, the another is in Budapest, Hungary. I use

rsync rsync://remote_box/remotedir localdir/ -zcvr --progress --size-only

The issue is that the remote server sends the filelist very slow.
Looking into the rsyncd process with strace shows that rsync reads all the
files from byte to byte, and after receiving the filelist, rsync client
does the same. The aim would be sync depending only on the size and the
existence of the files, not comparing each other.
If this is RTFM, please give me the correct RTFM://

TIA,
Wigyori
Zoltan HERPAI