What are the DIP switches set to? It can vary between cards, but sometimes the DIP switches will set slower memory access via wait states for compatibility.
Take a look here for an example: http://www.verycomputer.com/171_ce1703d62d4ad51a_1.htm

What are the rest of your system specs?
Another thing to check might be your ISA bus speeds, my 386 board has jumpers to set this, which can have a negative effect on performance if it's not set optimally.

Thanks for the reply😊
The dips dont seem to effect anything, I'd assumed because there's a db9 that it does a bunch of graphics modes and the dips are for setting that. Going through the permutations didnt change the speed. On an et3000 plugging into the db15 for vga disables the dips, think it may the the same here. I think the card in that post was one where there was only a db15 and some dips to configure that, I know there are some et4000s like that. Im running it on a slot 1 with a celeron333 and 128mb which is what I use for benchmarking up to early agp.

charliegolf wrote on 2022-08-23, 10:43:

I have this tseng et4000ax, I've benchmarked it and it runs very slow, more like an et3000. In fact the board looks more like an 3000 than a 4000. Has anyone seen a 4000 like this? and if so any ideas why it might be running at half speed? I've swapped memory so far and that made no difference.

The magic sauce that makes the ET4000 chips so fast is 0WS operation. For that, the ET4000 chip pulls down the /0WS signal on ISA pin B8 whenever it detects an access to video memory. Some cards have jumpers to interrupt the connection. You card seems to have all jumpers replaced by fixed connections. Try to trace out whether ISA B8 ends at a "jumper replacement", and whether you could modify the card to connect that pin somewhere.

Cool, thanks for the info. Ill do that and probably put in the missing jumper block. Just looked and the card isa has no trace at b8 🙁

charliegolf wrote on 2022-08-24, 06:46:

Cool, thanks for the info. Ill do that and probably put in the missing jumper block. Just looked and the card isa has no trace at b8 🙁

No trace at B8 means that the maximum performance you could ever achieve is 1WS, which is 5,3MB/s. Many 486 ISA bridges add another waitstate, so 4MB/s is the highest speed you are likely to see in a 486 mainboard. I will check my ET4000 ISA cards to find out where B8 is connected to on 0WS capable cards, so you could try adding a bodge wire.

charliegolf wrote on 2022-08-24, 06:46:

Cool, thanks for the info. Ill do that and probably put in the missing jumper block. Just looked and the card isa has no trace at b8 🙁

Both ISA ET4000AX cards I have at hand connect Pin 87 (SFDBL) to pin B8 (0WS) via a jumper. This connection offers every 16-bit memory cycle as 0WS cycle to the mainboard. This is likely not ISA conformant, because the card can not handle every cycle with no wait states (like if the internal buffer is full, or a read that contends with image scanout), so the chip also provides an output to add extra waitstates to the cycle. Activating both "more waitstates required" and "0WS" at the same time is specified to have 0WS override IOCHRDY, but obviously the ET4000 cards require it the other way. They still work in all 16-bit ISA mainboards I plugged them to.

Just quickly checking Programmer's Guide to the EGA and VGA Cards book by Richard F Ferraro, you might be able to use DOS "debug" to check the config of the card. At least, if I am reading it correctly.

Maybe something like:

1mov dx,3d4h
2mov al,36
3out dx,al
4
5mov dx,3d5h
6in al,dx

Check the bit 6 in AL.