The IBM 5170 case is AT-style, this means that any AT or Baby-AT motherboard can fit into the case. Even some rare AT Socket 478 motherboards, such as Commate P4XB. But after the upgrade the IBM PC AT 5170 will no longer be an IBM 5170, it will be a some AT-compatible computer in the old IBM case.. Probably the IBM PS/1s based on the 286 are the same way. For the PS/2Model 50, 50Z, & 60 (which are the only microchannel PS/2s based on the 286) the 287 is run at same speed as the 286 (10MHz). Many clone 286 motherboards, especially those able to run the 286 at speeds above 10MHz, had a jumper setting to adjust this.
The AT is IBM PC compatible, with the most significant difference being a move to the 80286 processor from the 8088 processor of prior models.Like the IBM PC, the AT supported an optional math co-processor chip, the Intel 80287, for faster execution of floating point operations.. In addition, it introduced the AT bus, later known as the ISA bus, a 16-bit bus with backward compatibility with 8.. The Intel 80286 [4] (also marketed as the iAPX 286 [5] and often called Intel 286) is a 16-bit microprocessor that was introduced on February 1, 1982. It was the first 8086-based CPU with separate, non-multiplexed address and data buses and also the first with memory management and wide protection abilities.It had a 16 bit data size and address width of 24 bits which could address up to 16M of.