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IBM Blue Lightning?

Blue Lightning is not the same as Cyrix. Blue Lightning was a purely IBM design based on the processor license they had from Intel. Cyrix was a separate company. The only possible confusion is that Cyrix used IBM chip foundaries for a while, so IBM was producing both it's own processors and Cyrix processors.
 
My foggy memory reveals a little more ...

IBM's license to the 486 processor at the time did not let them sell the processors as stand-alone chips. They had to be packaged as part of a motherboard or a complete system. So the only way to get them to end users was to sell upgrade packages or complete motherboards.

So yes, they probably were used as upgrades to existing IBM PS/2 machines. But it would have been a processor card or motherboard swap, not an 'overdrive' type upgrade.
 
Thanks for the information everyone.
This thing is surely going in the cpu box(a stupid collection of CPUs I have, only rare one is a strange vli from a wang server)
 
My foggy memory reveals a little more ...

IBM's license to the 486 processor at the time did not let them sell the processors as stand-alone chips. They had to be packaged as part of a motherboard or a complete system. So the only way to get them to end users was to sell upgrade packages or complete motherboards.

So yes, they probably were used as upgrades to existing IBM PS/2 machines. But it would have been a processor card or motherboard swap, not an 'overdrive' type upgrade.

Yes, indeed. One use of the IBM Blue Lightning processor (also known as the IBM 486SLC) was in Evergreen Technologies' "REV TO 486" module. That module was designed to upgrade Intel 386SX systems to the IBM 486SLC processor, and also included a 16KB L1 cache. The module would double the clock speed of 25 MHz and 33 MHz systems, and triple the clock speed of 16 MHz, 20 MHz, and 25 MHz systems.

I successfully installed such a module in December 1995 on my IBM PS/2 55SX and the upgrade worked fine. It upgraded the 386SX/16 to a 486SLC/48, allowing the Windows 3.1 system to run quite a bit faster.
 
Yes, indeed. One use of the IBM Blue Lightning processor (also known as the IBM 486SLC) was in Evergreen Technologies' "REV TO 486" module. That module was designed to upgrade Intel 386SX systems to the IBM 486SLC processor, and also included a 16KB L1 cache. The module would double the clock speed of 25 MHz and 33 MHz systems, and triple the clock speed of 16 MHz, 20 MHz, and 25 MHz systems.

I successfully installed such a module in December 1995 on my IBM PS/2 55SX and the upgrade worked fine. It upgraded the 386SX/16 to a 486SLC/48, allowing the Windows 3.1 system to run quite a bit faster.

There were a couple different "Blue Lightning" CPUs/daughtercards, so it creates some confusion. I believe Intel didn't licence the 486 level to anyone, all companies had to reverse engineer it themselves (IBM was allowed to improve the 386SX codemask, which gave rise to the IBM 386SLC, 486SLC2, and 486SLC3). The 386SLC has 8Kb L1 cache; 486SLC2 and 486SLC3 have 16Kb L1, with the last digit in the model marking the clock multiplier (all of those CPUs are 16-bit data, 24-bit address bus).

IBM made 486SLC2 daughtercards for the PS/2 Model 50 and 50Z, had a 486SLC2-50 CPU on the PS/2 Model 53 (like an updated 55SX), and has 386SLC, 486SLC2, and 486SLC3 planars and upgrade daughtercard levels for the Model 56 and 57. There was a 486DLC2 "Blue Lightning" daughtercard upgrade for the PS/2 Model 70 and 80. Plans weren't followed through to have a 486DLC2 CPU on certain models of the Model 76 and 77 (Intel 486 CPUs were used instead).
 
More than just reverse engineering

More than just reverse engineering

Processors like the IBM 486SLC were more than just a product of reverse engineering. Intel allowed IBM to improve it's 386 and 486 chips for use in IBM computers. From http://query.nytimes.com/gst/fullpage.html?res=9E0CEFDE143DF936A25752C1A964958260&pagewanted=all: "Intel and I.B.M. have a technology-sharing agreement that allows I.B.M. to produce its own versions of the chip, and the Thinkpad 700C uses a variation of the i486SL chip, called the 486SLC." See also http://en.wikipedia.org/wiki/IBM_486SLC.
 
Processors like the IBM 486SLC were more than just a product of reverse engineering. Intel allowed IBM to improve it's 386 and 486 chips for use in IBM computers. From http://query.nytimes.com/gst/fullpage.html?res=9E0CEFDE143DF936A25752C1A964958260&pagewanted=all: "Intel and I.B.M. have a technology-sharing agreement that allows I.B.M. to produce its own versions of the chip, and the Thinkpad 700C uses a variation of the i486SL chip, called the 486SLC." See also http://en.wikipedia.org/wiki/IBM_486SLC.

It´s actually a 486SLC2 on the TP 700/700C (and also the TP 720/720C). The Intel 486SL is a 32-bit data/address CPU with an 8Kb L1 cache and internal math coprocessor (ultimately a low-power 486DX), without being clock-multiplied internally. In contrast the IBM 486SLC2 is a 16-bit data, 24-bit address CPU (more like an enhanced 386SX, with 16Kb L1 cache, a 486SX instruction set, internal clock-multiplied, but no math coprocessor). As further evidence the copyright on IBM 486SLCx CPUs is ¨1985 Intel (the development year of the 386DX), 1991 IBM¨.

The copyright on the Intel 486SL is ¨1989 (the developmental year of the 486 class CPUs), 1992 Intel¨. From the New York Times article quoted:

...Within moments of the news last week [the article is 15 November 1992] that the Intel Corporation was introducing a new chip designed specifically for portable computers, Compaq, NEC and AST Research announced new notebook computers that would use it.

The new chip is the i486SL, the fourth member of Intel's 486 family...

An entirely different architecture between the two CPUs, with the Intel 486SL coming later in the game than the IBM 486SLC2. Do you want to know another kicker? The IBM 386SLC (which is based on a 386SX form-factor, not the Intel 386SL or 386DX) can even run all Intel 486SX instructions (probably cheaper to licence something as a ´386´ rather than a ´486´ from Intel; IBM did not commercially release a non-clock-multiplied version named ´486SLC´, so this was probably in essence what would have been named that)!

In short, the Times article (at least for that snipet) is all wet...

The wiki article has holes too (the 486SLC2 CPU upgrade is designed for the PS/2 Model 25 286, not the 8086-based version)...
 
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