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Found some old cpu's


Awhile back I bought a toolbox at an auction. Found these in there;
Cyrix dX4 100 Cx486DX4-100GP
Intel Pentium MMX

I’m trying to upload a pic from my phone, bare with me.

What were these mostly used for? The toolbox looks like it was used for some type of computer maintenance. I see diodes, some 8mb ram, switches and other electrical components I know nothing about. Any info appreciated. Era looks like early 1990’s.


@Aremis might know.




Also has some unmolested 4"x6" 2-side copper clad PCB boards and one PCB board sealed in black plastic that needs developing…


Normal desktops. They coulda been replaced or had been handy upgrades.

A cyrix DX4 is the same as an i486 at 100 mhz. It should say 4x86 or something on it. The pentium MMX was the big cheese after the first pentium came out.


Killer Doom CPU
This was when having a cpu multiplier was a new idea, before this everything ran on the same clock. With the DX50 this started to cause problems with everything at 50mhz.
The dx2/66 was 66 mhz with everything else at 33 mhz.
dx4/100 was the cpu tripled to 99mhz with a base clock of 33mhz.
No one wanted to name a cpu a DX3 so they just called it a DX4 even though it was tripled and not quadrupled.

In some benchmarks and in Doom the dx4/100 was very close to the new (and expensive) Pentium 66 and Pentium 60. Intel started holding back production of the dx4/100 to force people to go with the Pentium.

Cyrix along with AMD were lower cost alternatives to intel. I remember at Fry’s a dx2/50 CPU and MB cost about the same as an Intel 386 CPU+MB.

These were also the days when you could install 256k of level2 cache on your MB for another speed boost.
Hope this helps :slight_smile:


Between me and my friends we owned all of these. Cyrix provided extra competition, back then you had choice between Intel, Cyrix and AMD. The fastest Cyrix I owned was a MII 333 which ran at ~ 250MHz but supposedly performed like an Intel Pentium @ 333 MHz. When I went to a LAN party I learned the hard way that the new PII at 333MHz stomped all over it - that must have been in 1998. After that I was AMD or Intel for every build.

This is a good video about Cyrix and it’s exit from the CPU market:


those were the days :blush:





Too bad there isn’t onboard memory that I could access.