I have the exact same problem. It worked fine under jaguar, but under panther it is ungodly slow. When i'm on one of my pc's and browse to the mac and copy a file over it's horridly slow, the other way is fine though. If i however use ftp and transfer from the pc to the mac it's fine. So this indicates to me it's something with samba. I guess using a release candidate instead of a final release of samba wasn't the best call on apples part. I've been looking all over for an answer but so far nothing. The strange thing is, it doesn't seem to be everyone. Just for reference, i did a clean install of pather. I also messed with the 10/100/1000 settings as well as full and 1/2 duplex settings, no difference.