IBM used Cyrix processors. So they should perform the same. Intel/AMD 486 processors are faster per clock. Especially the ones with 16KB and WB cache (like Intel SK096 - only Cyrix 5x86 is faster per clock).

But which have higher quality assurance ?
Which have better build quality ?
Is there anyway to tell ?
Is it better to buy an IBM 486dx2 CPU or Cyrix 486dx2 ?

IBM made all Cyrix cpus. So there shouldn't be any difference. Buy the brand you like better 😉

IBM and SGS Thompson manufactured the chips for Cyrix. Cyrix was a fabless CPU designer. The IBM chips were identical to the Cyrix ones except in how they were marked. I don't know if this applied to all of the chips, but in the case of the IBM 5x86C, IBM is said to have been more conservative with the way the chips were rated, and in my opinion this is likely true because they tend to be pretty good overclockers.

Anonymous Coward wrote:

IBM and SGS Thompson manufactured the chips for Cyrix. Cyrix was a fabless CPU designer. The IBM chips were identical to the Cyrix ones except in how they were marked. I don't know if this applied to all of the chips, but in the case of the IBM 5x86C, IBM is said to have been more conservative with the way the chips were rated, and in my opinion this is likely true because they tend to be pretty good overclockers.

Where were the IBM CPU manufactured ?
The CPU reads "Copy right USA" but where were they manufactured ?

Intel486dx33 wrote:

Anonymous Coward wrote:

IBM and SGS Thompson manufactured the chips for Cyrix. Cyrix was a fabless CPU designer. The IBM chips were identical to the Cyrix ones except in how they were marked. I don't know if this applied to all of the chips, but in the case of the IBM 5x86C, IBM is said to have been more conservative with the way the chips were rated, and in my opinion this is likely true because they tend to be pretty good overclockers.

Where were the IBM CPU manufactured ?
The CPU reads "Copy right USA" but where were they manufactured ?

Difficult to know for sure unless you know how to read all the markings on the CPU. SGS Thomson (ST) manufactured chips would probably have been made in France or Singapore. IBM manufactured chips might have been made in the US, but I can't find any lists of 90's manufacturing plants. Many plants have changed ownership over the decades, some have been shut down, so it's not that easy to track down.
Cyrix branded chips could come from either IBM or ST.

kixs wrote:

IBM used Cyrix processors. So they should perform the same. Intel/AMD 486 processors are faster per clock. Especially the ones with 16KB and WB cache (like Intel SK096 - only Cyrix 5x86 is faster per clock).

IBM also produced and used Intel processors and called them Blue Lightning. Here is one that I own:

So if the CPU in question is an Intel clone it is faster than the Cyrix, otherwise they are basically the same silicon.

Originally, IBM produced for intel, but later they switched the Cyrix cores. The CPU shown above is NOT a blue lightning, but rather an intel 486 made by IBM. The actual blue lightning was a special hybrid chip intended only to be used in IBM's own hardware. It was a 386DX type CPU with 16kb cache and usually clock doubling or tripling. There was 386SX based version called the 486SLC. After IBMs contract with intel expired, Cyrix continued to use the "Blue Lighting" name on their 168-pin Cyrix 486 chips (but they aren't real blue lightnings).

I am quite certain that SGSThompson made some of their CPUs in Canada. I've seen a few.

I stand corrected. 😵