AlessandroB wrote:

[...]

Unfortunately I don't have a DX4 to do the test, and this mainboard only accepts 5V and a DX4 overdrive is really expensive and you have to buy it without going to trial.

Then test it the other way round: underclock your DX2-66 to 50MHz (2x 25MHz). That will keep ISA VGA performance constant and drop CPU performance by 25%. If the slowest parts of the game get even slower, you have a CPU bottleneck. If different parts of the game now get slower, but not much change at the formerly slowest parts, you had a VGA bottleneck.

Note that it's entirely possibly both CPU and VGA are limiting at the same time. In that case upgrading either will help - although as stated the ET4000AX is about as fast as it gets on ISA, if you can't go to EISA/VLB/PCI, your VGA is already maxed out.

dionb wrote:

AlessandroB wrote:

[...]

Unfortunately I don't have a DX4 to do the test, and this mainboard only accepts 5V and a DX4 overdrive is really expensive and you have to buy it without going to trial.

Then test it the other way round: underclock your DX2-66 to 50MHz (2x 25MHz). That will keep ISA VGA performance constant and drop CPU performance by 25%. If the slowest parts of the game get even slower, you have a CPU bottleneck. If different parts of the game now get slower, but not much change at the formerly slowest parts, you had a VGA bottleneck.

Note that it's entirely possibly both CPU and VGA are limiting at the same time. In that case upgrading either will help - although as stated the ET4000AX is about as fast as it gets on ISA, if you can't go to EISA/VLB/PCI, your VGA is already maxed out.

I cant't because because my IBM PS/1 is restricted to 33Mhz fsb.
but I did another test. I put two ISA graphics cards that I have in my collection in a PC with a PentiumII 233Mhz. In this way the CPU was not a bottleneck and I could see how much an ISA graphics card affects it. Unfortunately I don't have an ISA card with the Tseng 4000AX but I have two more that I think are similar or slower: a Cirrus Logic CL-GD5401 and an Oak OTI-087. In both cases, Doom was perfect, very fluid. This means that using a very fast CPU with a very slow ISA card does not damage the performance of Doom, and in my IBM PS / 1 the bottleneck is the 486DX2, and probably to a lesser extent the 30Pin ram.

HanJammer wrote:

ET4000AX is just a little bit faster than the better Cirrus Logic or Trident chips - maybe a bit faster. Nothing fancy. One reason why it maybe sought after is that it can be used (for some reason, which is not really an interest to me) in Atari ST machines...

If you want top speed from ISA card you would have to look for ET4000/W32i or ATI Mach 64 card...

I had an unusually fast JCIS mother board in '94 with a 486 66 and ISA, Wingine (proprietary) (system was put together to run NEXTSTEP for Intel 3.22 and Wingine was the fastest frame buffer around), and VLB slots. I added a Hercules Dynamite Power card, which had a Tseng ET4000/W32p, which is faster than the W32i. And it had 2MB interleaved DRAM so was full tilt. It was the fastest VLB gfx card out there for DOS. And a contact I had in engineering at Hercules had never seen a higher 3DBENCH score on that card from anyone else.

Just a few years ago I rebuilt that DOS PC, which ended up as a 5x86 160 in the end -- with VLB running at 40MHz instead of just 33MHz. I looked around and found a Cardex ET4000/W32p card with 1MB DRAM and empty sockets, so I expanded to to two for full throughput and it screams for DOS games. It's basically the fastest "486" DOS game machine one can have. (And it's got a GUS in it, as well.)

https://bytecellar.com/2014/03/11/behold-the- … ld-is-complete/

So, VLB + W32p is as fast as you can go for DOS gfx. I encourage it.

bp

blakespot wrote:

I had an unusually fast JCIS mother board in '94 with a 486 66 and ISA, Wingine (proprietary) (system was put together to run NE […]
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HanJammer wrote:

ET4000AX is just a little bit faster than the better Cirrus Logic or Trident chips - maybe a bit faster. Nothing fancy. One reason why it maybe sought after is that it can be used (for some reason, which is not really an interest to me) in Atari ST machines...

If you want top speed from ISA card you would have to look for ET4000/W32i or ATI Mach 64 card...

I had an unusually fast JCIS mother board in '94 with a 486 66 and ISA, Wingine (proprietary) (system was put together to run NEXTSTEP for Intel 3.22 and Wingine was the fastest frame buffer around), and VLB slots. I added a Hercules Dynamite Power card, which had a Tseng ET4000/W32p, which is faster than the W32i. And it had 2MB interleaved DRAM so was full tilt. It was the fastest VLB gfx card out there for DOS. And a contact I had in engineering at Hercules had never seen a higher 3DBENCH score on that card from anyone else.

Just a few years ago I rebuilt that DOS PC, which ended up as a 5x86 160 in the end -- with VLB running at 40MHz instead of just 33MHz. I looked around and found a Cardex ET4000/W32p card with 1MB DRAM and empty sockets, so I expanded to to two for full throughput and it screams for DOS games. It's basically the fastest "486" DOS game machine one can have. (And it's got a GUS in it, as well.)

https://bytecellar.com/2014/03/11/behold-the- … ld-is-complete/

So, VLB + W32p is as fast as you can go for DOS gfx. I encourage it.

bp

Mine is 4000AX, totally different.