IBM 486SLC
Is an improved version of the IBM 386SLC, based on the Intel core. IBM 486SLC featured 16Kb of L1 cache and the i486 instruction set. It had 1.349 mln. transistors and a 69mm² die. It was manufactured in 1992. It came in a 100-pin PQFP packge, with 33 MHz FSB speed. The 486SLC was also available in a clock-doubled version, the 486SLC2 (50,66 MHz), and later in a clock tripled-version, the 486SLC3 (60,75,100 MHz). Clock-for-clock, it was substantially faster than the similarly-named Cyrix part, yielding performance broadly comparable to a similarly-clocked 486SX in the 16-bit applications of its day. However, its narrow 16-bit bus, limited memory addressing capability (16 MB) and lack of on-chip FPU would prove to be major disadvantages under the new generation of 32-bit operating systems (such as Windows 95) that would become popular in following years.
It is suspected the clock tripled 486SLC3 part did not in fact actually exist as a stand alone product. All known instances of 486SLC3 CPUs are reportedly in the 132pin PQFP packaging with the extra address lines not connected (a 486BL3 running in 16-bit mode).
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