The x86 CPU landscape of the 1980s and 1990s was competitive in a way that probably seems rather alien to anyone used to the duopoly that exists today between AMD and Intel. At one point in time, Cyrix was a major player, who mostly sought to provide a good deal that would undercut Intel. One such attempt was the Cx486DLC and the related Tx486DLC by Texas Instruments. These are interesting because they fit in a standard 386DX mainboard, are faster than a 386 CPU, and add i486 instructions. Check your mainboard though, as these parts require a mainboard that supports them.

This is something that [Bits und Bolts] over at YouTube discovered as well when poking at a TX486DLC (TI486DLC) CPU. The Ti version of the Cyrix Cx486DLC CPU increases the 1 kB L1 cache to 8 kB but is otherwise essentially the same. He found the CPU and the mainboard in the trash and decided to adopt it. After removing the very dead battery from the Jamicon KMC-40A Baby AT mainboard, the mainboard was found to be in good working order. The system fired right up with the Ti CPU, some RAM, and a video card installed.

That’s when the excitement began, as although the mainboard is ‘Cyrix-aware’, its BIOS support is somewhat buggy. Although it technically will beat the living tar out of a 386, the Speedsys benchmark utility was crashing because the internal L1 cache wasn’t being enabled properly. Fixing the problem required an external Cyrix utility application. These issues were why so few people were interested in bolt-on solutions. The sentiment extended to Intel with their ill-fated Pentium OverDrive products.

For enthusiasts looking for a good deal, they were an exciting option, but Intel took offense to Cyrix barging into the x86 CPU market without a negotiated license. Cyriz instead utilized reverse engineering to make their own x86-compatible designs. This included their later 5×86 and 6×86 CPUs. After a series of lawsuits Cyrix was merged into National Semiconductor and later sold to AMD, who sold Cyrix’s latest designs under the Geode name before discontinuing it in 2019.