.... The AMD Athlons & Durons are K7 or 786. 3 integer math (ALU) units and 3 floating point math(FP) units
.... The intel Pentium & PentiumMMX was P5 core or 586 or "Pentium-class" (As was AMD K5). 2 ALU, 1 FPU
.... PentiumPro (PPRO), PII, PIII, Celeron are P6 or 686 (as was AMD K6-x) 2 ALU, 1 1/2 FPU
.... Pentium4, P4, or as we call it PIV, claims to be P7 or 786, but looks and performs more like a doctored PIII. 2 ALU, 1 FPU, lots of gimmicks
.... ALU's tend to be used in general business applications(apps.), web surfing, chat, etc.
.... FPU's tend to be used for newer games, 3D apps., CAD, CAM, etc.