I am no expert in this matter, but the level of complexity involved has probably prevented such efforts from succeeding . My guess is that something like this will come about eventually by way of an FPGA .

An FPGA system would be fine would be cool if they managed to put ISA slots for real cards but simulated ones would hopefully be ok as well.
Sounds like I may have to settle for buying original hardware if I want a 486 system in the mean time though.

The closest thing to a modern 386/486 is some industrial SBC's which have Vortex86 SX or DX processors.. however they are clocked higher and support more advanced I/O. You can basically think of it similar to an Amiga accelerator board, but in place of a 386/486/5x86. There's also a Vortex86 MX version supporting MMX.

I have a Vortex86 DX SBC, but I haven't messed around with it yet to see what type of downclocking I can do (if even possible) or how well it benches/games. It uses a 16-bit ISA slot backplane, so running any ISA card(s) in conjunction with it is possible.

I like the sound of this Vortex86 gonna do some googling to find out more about it. Thank you for making me aware of its existence!

wiretap wrote on 2020-04-27, 02:25:

The closest thing to a modern 386/486 is some industrial SBC's which have Vortex86 SX or DX processors.. however they are clocked higher and support more advanced I/O. You can basically think of it similar to an Amiga accelerator board, but in place of a 386/486/5x86. There's also a Vortex86 MX version supporting MMX.

I have a Vortex86 DX SBC, but I haven't messed around with it yet to see what type of downclocking I can do (if even possible) or how well it benches/games. It uses a 16-bit ISA slot backplane, so running any ISA card(s) in conjunction with it is possible.

Is this it? https://www.wdlsystems.com/ICOP-VDX-DIP-ISARD … 4-pin-ISA-256MB

I don't see any pics that show the ISA slots or really any ports for that matter but it sounds like you said its on the back? Or am I misunderstanding this?

You need something like this
https://www.amcuk.com/amc_pca6743f.php

plugged into something like this
https://buy.advantech.com/Boards-Cards/Embedd … 725991248&f=AEU

darry wrote on 2020-04-27, 02:55:

You need something like this https://www.amcuk.com/amc_pca6743f.php […]
Show full quote

You need something like this
https://www.amcuk.com/amc_pca6743f.php

plugged into something like this
https://buy.advantech.com/Boards-Cards/Embedd … 725991248&f=AEU

Thank you now I just have to find where I can buy a AMC-PCA6743F or similar product.

wiretap wrote on 2020-04-27, 02:25:

The closest thing to a modern 386/486 is some industrial SBC's which have Vortex86 SX or DX processors.. however they are clocked higher and support more advanced I/O. You can basically think of it similar to an Amiga accelerator board, but in place of a 386/486/5x86. There's also a Vortex86 MX version supporting MMX.

Vortex86 processors have more in common with Pentiums as in terms of performance and features the Rise mp6 was intended to compete at or exceed that level.

gdjacobs wrote on 2020-04-27, 04:04:

wiretap wrote on 2020-04-27, 02:25:

The closest thing to a modern 386/486 is some industrial SBC's which have Vortex86 SX or DX processors.. however they are clocked higher and support more advanced I/O. You can basically think of it similar to an Amiga accelerator board, but in place of a 386/486/5x86. There's also a Vortex86 MX version supporting MMX.

Vortex86 processors have more in common with Pentiums as in terms of performance and features the Rise mp6 was intended to compete at or exceed that level.

I specifically mentioned the SX and DX variant. The regular Vortex86 is P5 compatible, while the SX (and I believe DX) are not and lack CMPXCHG8B. The SX lacks a FPU. They're far more in common with a 386/486 than a Pentium. (but faster) Also, these processors are different from the Rise MP6/SiS55x.

RetroGamer02 wrote on 2020-04-27, 02:45:

wiretap wrote on 2020-04-27, 02:25:

The closest thing to a modern 386/486 is some industrial SBC's which have Vortex86 SX or DX processors.. however they are clocked higher and support more advanced I/O. You can basically think of it similar to an Amiga accelerator board, but in place of a 386/486/5x86. There's also a Vortex86 MX version supporting MMX.

I have a Vortex86 DX SBC, but I haven't messed around with it yet to see what type of downclocking I can do (if even possible) or how well it benches/games. It uses a 16-bit ISA slot backplane, so running any ISA card(s) in conjunction with it is possible.

Is this it? https://www.wdlsystems.com/ICOP-VDX-DIP-ISARD … 4-pin-ISA-256MB

I don't see any pics that show the ISA slots or really any ports for that matter but it sounds like you said its on the back? Or am I misunderstanding this?

That looks like just a SoC module. I was speaking about a whole SBC which you plug into a backplane. Example of the one I have: https://www.advantech.com/products/1-2jkn7b/p … 18-d5cca41d4ff5

I think you guys are talking about two different standards PICMG and PC/104. Both can support ISA but with PC/104 its usually a custom ISA module almost never connected to a standard ISA slot. PICMG connects to a backplane and uses standard ISA, PCI, etc depending on which PICMG version (I’ve never seen AGP supported).

wiretap wrote on 2020-04-27, 13:04:

I specifically mentioned the SX and DX variant. The regular Vortex86 is P5 compatible, while the SX (and I believe DX) are not and lack CMPXCHG8B. The SX lacks a FPU. They're far more in common with a 386/486 than a Pentium. (but faster) Also, these processors are different from the Rise MP6/SiS55x.

Disabling features is not uncommon in embedded SoCs. Vortex86s (including SX and DX) are all super pipelined to the best of my knowledge, so they're not directly descended from DM&P's earlier 386 line.

The Vortex86 is purely a 486 core. Most on ebay you will find are the old lowend sx variant. its rare to see the 1.4ghz dx version show up.

picmg 486 SBC are dime a dozen.

if your hunting a vortex86 board, make sure you get all the io broken out, as the optional io breakout board is uncommon, and not all them have all the headers.

BloodyCactus wrote on 2020-04-27, 15:52:

The Vortex86 is purely a 486 core.

It's at the very least a hybrid as the cache architecture is more like a P5, it does some prefetching operations, etc. No confirmation that they applied any of the triple issue pipeline design. The programming guide is silent on that topic.

It supports a software configurable clock divider that can be set between 1 and 8, so that's nice for retro.

change the cache all you want. 486 core is 486 core. no mmx, no 3dnow.

straight from the manual;

This Vortex86DX processor core contains all the features of the 486SX microprocessor with enhancements to increase its
performance. The instruction set includes the complete 486SX microprocessor instruction set along with extensions to serve
new applications.

the enhancements + extensions are not cpu related (ddr memory/usb/pci/integrated ethernet mac, etc).

remember, vortex86dx is a cutdown rise mp6/sis550. the fpu is also not in hardware (does not scale to the cpu core frequency) so they probably did it in microcode or something. It performs really badly apparently, 800mhz vortexdx is slower than a Cyrix 6x86 250.

Yes, I've had the same thought. I'd like to build a PC-compatible motherboard, but I want just a little more kick than Sergey's XT. Even at 9.54Mhz, just doesn't do it for me.

Reason for not making newer boards is probably an inability to track down chipsets in reasonable volume, coupled with greatly increased complexity. I know very little about such matters, but basically the AT is a more complex layer upon the AT which requires more BIOS code and support circuitry. The XT was a simpler machine, more in line with hobbyist SBC efforts.

There were boards without chipsets into the 386 and even 486 era. Mostly very early, very expensive boards with limited functionality and performance. They would fill an entire full AT board with chips just to achieve core functionality and perhaps DIP RAM sockets and a cache controller. These probably used rare, hard to obtain chips for some functions, were highly complex designs, and would be beyond the ability and budget of most hobbyists to build.

Here's a picture of such a board.
https://www.ebay.com/itm/VINTAGE-386-MOTHERBO … r-/312926027673

Also, doesn't the NuXT use a rare thirty year old XT motherboard logic chip, the FE2010A? In a sense, it's not so modern -- if it were, it's be running at the much greater speeds later NEC embedded 8088s attained.

This PICMG and PC/104 seems a bit complicated. Thank you all for your feedback but maybe Ill just end up buying an old 486 system off ebay.

BloodyCactus wrote on 2020-04-27, 23:50:

change the cache all you want. 486 core is 486 core. no mmx, no 3dnow. […]
Show full quote

change the cache all you want. 486 core is 486 core. no mmx, no 3dnow.

straight from the manual;

This Vortex86DX processor core contains all the features of the 486SX microprocessor with enhancements to increase its
performance. The instruction set includes the complete 486SX microprocessor instruction set along with extensions to serve
new applications.

the enhancements + extensions are not cpu related (ddr memory/usb/pci/integrated ethernet mac, etc).

remember, vortex86dx is a cutdown rise mp6/sis550. the fpu is also not in hardware (does not scale to the cpu core frequency) so they probably did it in microcode or something. It performs really badly apparently, 800mhz vortexdx is slower than a Cyrix 6x86 250.

Yes, I read the same material, although it is certainly light on detail and may only be providing an indication of the execution resources of the cpu. For the SX, that hints at a single issue pipeline and no FPU (which we know explicitly).

Prefetch units and discrete instruction and data caches were introduced in fifth generation cpus to allow the implementation of superscalar architectures without undue pressure on the memory controller. I wouldn't expect them in a warmed over 486. On the other hand, starting with a superscalar architecture like the plain jane Vortex86 then lopping off two pipelines and the fpu would leave you with something close to the SX.

Did they do this or go the other direction, grafting more advanced components from more powerful cpus onto an evolved 486 cpu core? That's really unclear.

Well we had rise mp6 which was a full but, slow and brittle but pentium compatible. SiS bought it out, turned it into a SoC, added sound and video hardware, the north + south bridge, onto the same die space this was the SIS550. Vortex bought that design, which became the original vortex86 (pentium compatible). they then cut pieces off to remove complexity and die size so they could add extra shit to the SoC core (ddr/pci/usb) into the single chip design, so more shit got sacrificed for that space. this became the vortex86sx with a 486sx level core (no mmx, etc).

the vortex86sx runs on 1 watt of power. 1 watt!