dx2 66 is clock doubled. VLBus runs at 1/2 or 33mhz. It's is a good cpu for overclocking tho, you maybe able to run the VLB faster if your video card can tolerate it and you have proper wait states.

Dx2 I want to say is the defacto 486. It should run win 3.11 fine and any game that isn't pentium class like quake or more demanding than doom. Deturboing gets you to 33mhz, 33mhz + L2 cache off gets you to like 386 speeds. Which will run somthing like original Wing commander without needs of patches.

Btw I do not know what VLB 66 and I never heard of it. VLB runs at 25-33 MHZ depending on multipliers. It can run faster like 40mhz with overclocking. DX266 is a clock double chip, DX4100 is a clock tripple chip. They both double or tipple 33mhz. Other chips run the bus at 25mhz and double, tripple, or go in .5 increments. Like a Pentium overdrive which is like 3.5 X 25 or something.

I would stick with VLB for the sole point of getting the full performance out of your DX2.

Even the fastest ISA cards like ET4000s quickly run out of steam and bottleneck the system when it comes to pixel pushing workloads. Mostly FPS games, but I think faster 2D titles like jazz and some demoscene productions would struggle aswell.

But you said your not interested in playing DOOM or the like so....if your feel a bit extra nostalgic for the early 486 Days. You should be fine-ish with a ISA/DX2 system.

Aslong as you keep potential bottleneck situations in mind.

You remind me of a machine a relative got that was decommissioned from a bank in the mid-1990s. I believe it was an ISA-only 486DX/33 with a Cirrus Logic CL-GD5426 video card.
I'd go with a VLB board; you can always just not use the VLB slots if you decide not to. As you'll be happy with 5-volt-only boards, pretty much any VLB board would suit you.
Don't forget that you can run IDE over VLB also, not just the video card.

Warlord wrote on 2020-09-21, 20:59:

Btw I do not know what VLB 66 and I never heard of it.

alfer wrote on 2020-09-21, 20:40:

How much more smooth "game coverage" I'll be able to squeeze out of VLB 66 (vs regular ISA DX66 or 33)? A twofold question.

I think he means how smooth is a VLB system with a DX/66 vs ISA system with the same CPU or a 33

alfer wrote on 2020-09-21, 20:40:

It's as simple as that:
2. I am building a 486 VLB machine with DX2 66 (mainly for sentimental reasons and to have a slow one for a few particular games), but have doubts if I'll fancy a classy non-VLB DX33 (66) more.

I would say this is your answer right here, No point building an ISA system if your just going to still dream of VLB.
You have the Pentium as your practical dos pc, this is your sentimental one. Go with what feels right and not worry about what it can and cant run.

I've got about 13 retro PC's , It's the ones with sentimental value that get used over the ones that could actually run the game better in most cases. (I DO play doom on my DX2/66 for this exact reason.)

Warlord wrote on 2020-09-21, 20:59:

Btw I do not know what VLB 66 and I never heard of it.

chinny22 wrote on 2020-09-22, 08:49:

I think he means how smooth is a VLB system with a DX/66 vs ISA system with the same CPU or a 33

Correct! Thanks for clearing the confusion, mate. No 3D chess here 😀.

I thought that DX2-66 is more suitable for an ISA build, that's all. But some smart people (including you) already stated that such a system would not be ideal, if only for the potential bottleneck.

alfer wrote on 2020-09-22, 10:22:

Correct! Thanks for clearing the confusion, mate. No 3D chess here :-). […]
Show full quote

Warlord wrote on 2020-09-21, 20:59:

Btw I do not know what VLB 66 and I never heard of it.

chinny22 wrote on 2020-09-22, 08:49:

I think he means how smooth is a VLB system with a DX/66 vs ISA system with the same CPU or a 33

Correct! Thanks for clearing the confusion, mate. No 3D chess here 😀.

I thought that DX2-66 is more suitable for an ISA build, that's all. But some smart people (including you) already stated that such a system would not be ideal, if only for the potential bottleneck.

Regardless of the CPU, ISA would be a bottleneck. Even in 386-period, ISA bus was the bottleneck. That's why MCA and EISA were developed.

In 486-period, VLB was introduced very early on in 1992 and became the de-facto standard by 1993. DX/2-66 was also a 1992 part, so it was a logical pairing - but particularly in the low end non-VLB boards persisted longer, and once the DX/4 parts (and P54 Pentiums) became mainstream, the DX/2 persisted in the low-end as it was the last 5V CPU that could run on the cheapest of motherboards.

So, if you're looking for a 1993-era high-end build, a DX/2-66 with VLB would be the obvious choice, and DX/2-66 with ISA wouldn't make sense - no one in 1993 choosing a very expensive DX/2-66 would par it with an old board. But a 1995 low-end build would very likely have a DX/2-66 on it, not necessarily with VLB (as if you wanted to pay for performance you would have gone 3.3V DX4 or Pentium).

Ya he made edit dx4 100 is faster but you sacrifice not being able to deturbo to 33mhz. Deturbo on the 100 I think only brings you down to like 66mhz that’s the problem