I'd recommend the Cyrix DX4 settings as well. TI made a clone of the Cyrix SLC & DLC chips, so the reasoning is they cloned a DX4 too.

The SXL2 has a much different pinout to a real 486 CPU, even though it can physically fit in the same socket.
1. The pinout is similar to an Intel SX (specifically the NMI pin).
2. The CLK is halfed. 33Mhz input would halve to 16Mhz, then internally double to 33Mhz.
3. Much of the 386 related BUSY/PEREQ/SUSP/SUSPA/SMADS/ERR/NA lines would not be connected to the SXL2 or have unspecified behaviour...

H3nrik V! wrote on 2025-05-12, 08:43:

Hi there, […]
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Hi there,

I'm looking for any experience in what jumper settings to use for this TI 486 on my 486SOM board.

red-ray suggest jumpering as a Cyrix 5x86, but we're not sure. Any inputs?

Bonus question; the SXL2 - that's some kind of souped-up 386, right? Would it ever get to work on this board?

As you can read in the manual there are 2 jumper settings for a Cyrix DX4.
My SGS-Thomson 486 has printed "STANDARD PINOUT" on it, so I have to choose the Cyrix DX4 (DX4 P/O). However, it looks strange because I'm used to set Intel DX4 (WB) settings for it. But if your DX4 has the former Cyrix pinout you need the setting Cyrix DX4.

For your SXL2 processor, you may try the settings for a Cyrix DX. You may need to short J2 when it has no FPU.
However, it may happen that your motherboard's BIOS is confused because of that weird CPU.

Take care on the right voltage and clock setting!

Unfortuneately there is not much information of the SXL2 on cpu-world.com
Please upload a picture to: https://www.cpu-world.com/CPUs/80486/MANUF-Te … nstruments.html
However there is a comment on this CPU series on https://www.cpu-world.com/CPUs/80486/Texas%20 … 486SXL2-50.html

Posted by: black_monolith 2007-06-30
The TI486SXL series are pretty interesting chips. TI made them in both 132-pin (386) and 168-pin (486) versions. They even made an SXLC varient for 386SX motherboards. This chip probably belongs in the 386 section, because it is infact based on the Cyrix DLC core. As far as I can tell the only difference is that TI increased the L1 cache size to 8kb. I run the 132pin ceramic version in my 386DX system, and the speedup is substantial...almost as fast as a real 486. That extra cache really helps.

So, the DX4-G100-GA runs as suggested as a Cyrix DX4 (DX4 P/O).

SIV identifies as Cyrix - BIOS reads TI486-DX4 (IIRC the dash correctly)

Sending files to Ray for analysis 😀

Edit: Corrected "(DX4 P/O)"

I'm a little more reluctant to take the SXL2 for a spin though - funny that there aren't any pictures on CPU-World. Pretty sure I bought it there as part of a greater lot ...

H3nrik V! wrote on 2025-05-12, 18:47:

I'm a little more reluctant to take the SXL2 for a spin though - funny that there aren't any pictures on CPU-World. Pretty sure I bought it there as part of a greater lot ...

I did it anyways ... 🤣 no POST as Intel SX/UMC SX, nor Intel/AMD DX/DX2

Also tried the Cyrix 486 DX4 (DX4P/O) to no avail

Could "Cyrix DX2V" maybe work? All though I doubt it the SXL2 has WB L1 cache?

The SXL2 didn't even heat up (set to 4V as I don't have a 3.6 setting)

Maybe a dud, maybe held in reset, maybe ???

Below you can see I can quite easily make SIV say Texas 486DX4, and the CPUID of 0481 matches the Intel DX4 of 0480 with a different stepping, but the $64,000 question is, "what does a Cyrix DX4 report?".

I don't have and can't find any documentation on what a Cyrix DX4 will report in the DIR + CCR registers so we need to get a dump from one. If you have one please generate similar to as below using SIV V5.81 Beta-07 or later and post it to this thread. Press the [_]CPUID check box to get the [CPUID CPU-0] dump, note the DIR + CCR register data should be the same on NT and 9x systems.

I am also wondering how many cycles an AAM takes on these DX4 CPUs, I just changed SIV to use 17 for the Texas DX4, the same as the Cyrix DX4 and with the revised number the speed should report as about 100 MHz.

Michal Necasek says: February 17, 2017 at 10:29 pm posted to https://www.os2museum.com/wp/whats-in-a-name/

I can’t find any documentation for the non-Cyrix-branded Cx486DX models. The documentation exists, just doesn’t appear to be available.

However, sources tell me that the Texas Instruments 486 DX2 and DX4 CPUs can be distinguished through the DIR0 register (contains 80h/81h rather than values in the 1xh range which Cyrix CPUs use). So far I see no hints that IBM- and ST-branded CPUs differ from Cyrix.

So I guess the Ti 486 DX2 will report 80h, if you have one or an IBM- or ST-branded CPU please will you post SIV dumps.