Your motherboard was manufactured by Magtron Technology Co (based on the BIOS ID string).

The results are more or less what I expected and what other users on the forum has also found.
Overall, you'll notice that there isn't a vast speed improvement over the standard Cyrix DLC CPU (since the TI CPU is actually a Cyrix DLC CPU but, with just 8K of L1 cache).

It would be interesting to see how each CPU compares on the Doom 1 Timedemo 3 benchmark but, with an ET4000AX ISA card, I suspect that you will have a bottleneck there. If you can find a "hybrid" 3/486 motherboard with VLB slots (with a VLB graphics card) then it would be interesting to see the performance comparison.

Still, I find the Cyrix/TI DLC & TI SXL CPU's very interesting.
So much that, back in 1993, I actually bought a Cyrix 486DLC-40 with its Cyrix math co-processor, instead of an Intel 486DX-33.

The grey-topped Cyrix FasMath FPU's are a smidge faster than the black-top ones. Someone mentioned that the black-top FPUs changed something to increase compatibility at the small expensive of performance. Landmark is sensitive enough to see the difference in speed. Unfortunately, the grey-tops don't usually work with the SXL when clock doubling is enabled.

Awesome thread! I have a PGA 132 version of the 486 SXL (9413FTB1 4031854). I recently read this website: https://x86.fr/the-uca-now-supports-ti486s-fe … sting-ti486sxl/ where the guy says an SXL 40 can be clock doubled by enabling a register if it's a B0 stepping. I have no idea if this applies to the 386 vintage but it sounds like it might.

A more general question I have is, other than this SXL-40, is there anything better for a 33MHz 386 setup? I mean if you can't change the crystal? I would obviously want to overclock the SXL2 but Feipoa says you can't do that. Maybe the silicon is no good. Then I heard there was a 33/66 with interposer in the works but I guess that's not done yet. So is there anything better for what I have now? I want to keep the bus speed high and the cache high for maximum benefit to the bottlenecked 386 and it seems the SXL-40 is the ticket. But it can't hurt to ask if there's something better.

You can use an SXL2, but you may need a black-topped or DLC type Cyrix FasMath when clock doubling. This may also depend on if you are using SCSI; I no longer recal the details. More info here: Re: Register settings for various CPUs The SXL2 is set to 1x by default. Use DOS software to set 2x. You will need to experiment with the math co-processor selection.

The SXL2-66/80 interposer board has been sufficiently finished for some time and it works well. Assembly may not be for everyone though. Evergreen and Powerleap also made an SXL2-66 interposer. Evergreen used the QFP chip while Powerleap used the PGA.

You can use a clock tripled IBM Blue Lightning BL3 at 66, 80, or 100 MHz. There are various upgrade options, from Evergreen to IODATA and Buffalo. Some photos in this thread: 386 upgrade kits and the Transcomputer 486HPi - Am5x86-160 anyone?

Sometimes the logic on this BL3 boards gets in the way of it working properly, so you may also want to take a BL3 chip and solder it to a 386DX QFP-to-PGA interposer, as shown here: Creating a voltage regulated 386 BL3 module from existing parts Some people also run at 5V and bypass the 3.3V.

Yes, you can change the crystal oscillator on your 386 board. You'd use a 66 MHz crystal oscillator for a 33 MHz FSB, an 80 MHz crystal for a 40 MHz FSB, etc. You can also make variable crystal oscillators, e.g.
386 Clock Generator Replacement
Re: Project: Full Can Clock Oscillator Replacement

The fastest upgrade options for a 386 are:

1) using a Transcomputer upgrade module with an Am5x86 at 160 MHz
2) using an IBM Blue Lightning BL3 upgrade module at 2x50 MHz or 3x33 MHz
3) using the custom PGA-168 to PGA-132 interposer PCB with SXL2-66 at up to 90 MHz (2x45). Nearly all CPU samples can run at 80 MHz with the right voltage.
4) use a Cyrix DRx2-66

Some 386 boards tend to be optimal with the BL3, like the SiS Rabbit, while others have benchmark numbers skew in favour of the SXL2 (Symphony Haydn II).