slow send speeds on network

[Zac67]

Sounds like a duplex mismatch; possibly NWay isn't working properly.
I'd try with duplex forced on and off and see which one works better. There's a chance that currently the switch sets duplex to on while the Amigas switch it off. Forcing it on might reverse the problem, so the only solution would then be to force it off.

Obviously with ADSL connections, upload is always slower than download, but 20-25 KB can usually be expected with 3 Mbps (384 or so upstream).

Additionally you might want to try an increased RWIN parameter for internet downloads; that way more data can be on its way before an ACK is required (especially for higher latency connections).

[Zac67]

can you force the duplex from the amiga side? i think the switch is set to auto detect, but seems to pick up 100Mb full as a preference and work down till it connects ;-)

A true switch always supports FD but requires autonegotiation (NWay) to work - if it fails (due to possible driver issues) it'll drop back to HD.

One puzzeling thing. when pushing stuff to the PC share over the lan from the amiga, the PC seems to think there is upto 80percent network utilization on the 100Mb segment. but there is no way the amiga is pushing 8-9MB of data a second.

Sounds very much like duplex mismatch (Amiga HD, switch FD) - possibly the jam signals are picked up as network utilization, depending on the switch. A fully switched segment is totally collision free. Check this pretty good Wikipedia article on duplex mismatching.

You might also want to try another (brand) switch and/or a hub if you've got one at hand.