Wow very good to know.

Marco wrote on 2025-10-27, 18:08:

Thanks for the hint. There are unfortunately no packet drivers available for the 515 😒

Bummer... I've run into very few cards where there isn't a packet driver (or one for a compatible card).

To be completely honest however, although I had dozens of NICs back in the day (and still have a few, even a couple
ISA ones) which I use on the 4-5 DOS systems I still have, I don't tend to try and run DOS on my newer systems, and
haven't needed to go looking for newer packet drivers. In the very rare cases where I've booted DOS on something
newish for testing - I can usually just stuff in a PCI card if I need networking.

I'm sure most newer hardware doesn't have need for packet drivers as DOS has been almost eliminated
from "modern" consideration factors in picking an OS.

So Tests conducted:

SMB Large file Transfer (15MB):
DOS: 428kb/s
WIN311: 788kb/s
WIN95: 750kb/s

FTP Large File Transfer (from Slackware)
WIN31: 837kbps
WIN95: 1120kbps

Not to NUL but fast HDD. Couldnt get wsftp to download to NUL

Further remarks:
- switch port config is in line with NIC config 100MB HD

So at the end I couldn’t get closer to a possible root cause.

I might test another router. But from the current I do easily get 6MB and more for SMB download speed from a modern PC.

My ISA Bus achieves up to 4400kb/s for linear HDD reads so even without busmastering these results are disappointing and more or less identical or slower then the ones of a 3c509.

Next steps:

1. Use another router (for another ftp test)
2. Test the card in my 486dx2 80 as proposed.

Anyway maybe these results do already give someone some more hints?!

Thank you

Marco wrote on 2025-10-27, 21:59:

Not the NUL but fast HDD. Couldnt get wsftp to download to NUL

You mean you're using the WS_FTP client?

My preferred setup is:

• FTP server on a modern PC
• FTP client on the machine being benchmarked
  • DOS - FTP.EXE from mTCP, with "MTU 1500"
  • Windows 3.x - FTP.EXE from TCP/IP-32, even when using some other TCP/IP stack
  • Windows 9x/NT - FTP.EXE shipped with the system

All three clients can download to NUL.

Anyway maybe these results do already give someone some more hints?!

They look OK for a CPU with 16-bit bus.

Will try now with local FTP on the router itself.

Results:
- Download performance from Modern PC (wifi, to HDD):
--- FTP: 3,35 MB/s
--- SMB: 3,45 MB/s

- Download performance from Testsystem TI486SXLC2 (LAN):
--- WIN95 - FTP.EXE: 467kb/s
--- WIN95 - WSFTP: 520kb/s
--- WIN311 - FTP.EXE: 760kb/s
--- WIN311 - WSFTP: 551kb/s

So all benches now conducted with the testsystem.
Very disappointing.

Again - my conclusion was that 100 Mbps NIC doesn't make sense in a 386, and I was testing 386DX, with 32-bit bus!
Re: Expected network throughput on ISA network cards

Seems like I simply have to accept that fact as well 😀

I was at least hoping for CPU usage reduction by DMA Busmaster. But as always mentioned here in the forum: seems to be black magic and no one really knows if it's working / used.

Again - thanks to everyone

It remembers me on my tests with an EISA 3Com 3C597 (100 MBit/s) in a 486DX50 with an Adaptec 2740W EISA SCSI controller:
EISA: Win95C --> Windows 10: 14.5 MBit/s (from cache)
EISA: WinNT 4.0 --> Windows 10: 25 MBit/s (from cache), 22 MBit/s (from disk)
Re: Why are 3Com NICs regarded in such high regard?

Great results.

I could extend my testings:

1. make NDIS message „Dma busmaster disabled“ disappear by doing auto Dma tuning in config
- thanks for that hint upfront here which I really missed earlier
- results could be improved slightly but marginally

2. tested now on my system 2 (isa at 13,3MHz):
- DOS large file copy from SMB: 1152kb/s
- Win311 large file copy from SMB: 937kb/s
- Win311 large file copy FTP to NUL: 1520kb/s

There is indeed an increase but nothing close to even 50mbit. Again 100MB HD media type setting.

I get more and more the impression that a comment a read here somewhere was right: 515 is capable of allowing 100MB switch port configurations in large setups (auto config, homogen config, homogen switch systems, …) but cannot provide notably (!!) more bandwidth than the 509b.