I wouldn't expect that card to be any faster than 3C515.
"100 Mbps" ISA cards are faster than 10 Mbps ones, but can't even approach 100 Mbps.
ISA is too slow for that, period.

Yes I know. The point is that I only experience 300kbit for the moment. Maybe it’s only that the 386sx is the bottleneck and 100mbit wouldn’t bring any! improvement. My 3c515 indeed didn’t show any difference.
Ps. I ran isa at 15MHz

Marco wrote on 2024-10-20, 12:05:

The point is that I only experience 300kbit for the moment. Maybe it’s only that the 386sx is the bottleneck and 100mbit wouldn’t bring any! improvement.

Indeed, 386 isn't a good match for a 100 Mbps NIC:
Re: Expected network throughput on ISA network cards

Good link. Thanks.

The benefit of 100Mbps NICs on ISA isn't for the old PC itself but for the rest of the network. Back when these things were current hardware, Ethernet switches weren't a thing and everyone used hubs. Characteristic of hubs was that they were a shared medium so ran at one speed only, so if a single device on the network only supported 10Mbps, everyone used 10Mbps. Stick a 100Mbps card in that old 386 and it stays as dog slow, but (assuming you have a 100Mbps capaple hub) everyone else can keep networking at higher speeds.

With switches, each device has a dedicated link to the switch and there's no dependency between devices. I can have my server connecting at 10Gbps to my switch while a retro box only does 10Mbps. No problem. So ironically, 100MbE ISA Ethernet cards became less useful over time as 100Mb hubs disappeared.

Yes indeed that’s what I meant by my strange wording „performance Protokoll Exchange“ 😀