This listing is for a very rare 16Mhz Intel 486, the A80486SX-16. Very few of the 16Mhz versions were made and even fewer have survived. While thousands of most 486 versions are available, only a handful of SX-16’s still exist.  In addition, this is an SX545 low power version, used for mobile and other low power applications. The SX545 version was more tolerant of power fluctuations and its frequency was dynamically scalable from min to max speeds. The SX-16 is the entry processor, speed-wise, to the 486 family.

Intel introduced the SX series of the 486 as a low cost entry point to encourage 386 users to upgrade. The SX was a regular 486DX with the coprocessor disabled (essentially a better 386). In an odd move, a 487 coprocessor was “created” for the 486SX.  So, theoretically, a 486SX, plus a 487 would equal a 486DX, right? Correct, and the complete answer is even more bizarre, because the 487 was actually a full 486DX. When the 487 was inserted in the coprocessor slot, the 486SX was completely disabled and 487 operated as the full 486DX that it was. You might think this is unusual, but Intel has done similar things going way back to its 1301/2, 1601/2, and 1701/2 EPROM/PROM family.

This chip is CPGA (Ceramic Pin Grid Array) with gold lid and pins/leads (this is a clean desolder, the lower thin part of the pins are covered with silver solder, it not very noticeable). No 486 collection is complete without this chip. This chip would make a great addition to your Intel collection.