It was a full-fledged 80486 processor with integrated Floating Point Unit. When installed into upgrade socket on 486 motherboards, the 80486SX processor was disabled, and the 80487 was used for both integer and floating-point calculations. After upgrade the original 80486SX CPU could be removed from its socket if desired.
我而家先知原來根本無487 co-processor呢回事，所謂487根本係就係486DX，插左上去之後就會直接閹左原本個粒486SX