1ST1 wrote on 2020-11-21, 08:54:
I have not checked the full thread of this on 12 pages, but what I saw is very interesting, but I can't see which benchmark tools are you using for this. Has anybody put the Cyrix/TI 486SLC in coparison? I know, it is a "486" CPU for 386 systems, and a quick benchmark in Checkit 3.0 says, that it has only about 50% as the saved value of a 80486-33 system, even with L1 cache enabled by the Cyrix tools. I have such a machine, and I could run the benchmarks if they are compatible, and I also would like to do the comparison with the original 80386-33, and I coud compare with ULSI387 Math Copro and IIT387, and as soon as I get hands on a Cyrix FastMath 387 and an original Intel 80387.
If you download the pdf files, then you will also see more detail around the testing methodology and the various benchmarks used (both under DOS & Windows).
I think one of the reasons why the Cyrix SCL/DLC CPU's were excluded, is because they don't fit on a Socket 3 platform.
The intention of this exercise was to keep (as far as possible) all the other components the same, apart from swopping out the CPU's - this was to obviously to ensure that there were no other variables in the testing that was performed.
Granted, there were some CPU's that were tested on other motherboards, but with the same chipset.
I seem to recall that @feipoa was planning on performing a similar benchmark exercise on the 386 platform, but I'm speaking under correction.
If you had said the Cyrix 486DLC, then I would say you perhaps have an interesting point, but I wouldn't regard a Cyrix 486SLC as being in the 486 class, since it runs on a 16-bit external data bus (like your 386SX CPU) which severely cripples its performance. At best, you will get the equivalent performance of a 386DX-33 with a 486SLC CPU (provided you can get the L1 cache to operate properly on the motherboard), but nowhere near 486 performance.
That being said, Texas Instruments (being a second source for Cyrix back then) also made a Cyrix 486DLC equivalent, called the TI486SXL with 8kb of L1 cache (both in 132-pin and 168-pin packages and even clock doubled versions), The 168-pin equivalent one could probably test on a similar setup to see how it stacks up against your Intel/AMD 486DX counterparts.
However, based on my own tests, a Cyrix 486DLC 40 MHz CPU runs just below that of an Intel 486DX 33 MHz CPU (in terms of integer performance). Considering that most 386 motherboards did not have VLB slots, this would also hinder overall performance compared to an equivalent 486DX-33 setup with a VLB grahpics card.
@feipoa did perform some comparative tests between a Cyrix 486DLC & TI486SXL - Cyrix/Ti 486DLC vs 486SXL