I486
From Computer History Wiki
The i486 is the 4th generation CPU from Intel based on the 8088/8086 CPU. The 486 was a 32bit CPU, featuring all the features of the i386 CPU. The 486 also included 8KB of l1 cache, and a math co processor built in.
Later cost cutting variations included the 486SX, which was die compatible with the original DX part, except it had its math co processor destroyed. The 487SX part was in fact a 486DX cpu.
