Using the System Programs (Refdisk or System Partition) 
   Go to the Diagnostic Main Menu and select Display revision levels (you might have to select More utilities first). Note the submodel code displayed on the screen. 
   Read the FRU number printed near the card-edge of the processor board. Look for a second label (marked P1 - PC) to the right of the front serial number of the system. The second label indicates that the processor board has been upgraded. 

Complex Type links take you to the page for that type. 

Mod	Sub  Mod  90	Sub  Mod  95	Processor Board  FRU Number  and Description	2nd.  Lab.	Complex Type
OGX	2D	2C	92F0049 486SX-20	--	1
OJX	11	14	64F0201 486-25	P1	1
OKX	13	16	64F0198 486-33	P2	1
OMX	2B	2A	92F0048 486-50	P3	1
OGX	2F	2E	92F0065 487SX-20	P4	1
OKX			92F0145 486-DX2-66 5		1
OHX	57	58	92F0079 486SX-25	P5	2
OHX	59	5A	92F0079 486SX-25 1	P6	2
OLX	3F	40	92F0161 486DX2-25/50	P7	2
OHX	5B	5C	92F0079 486-25/50 2	P8	2
OMX	29	28	82G2484 486-50  57F1597 486-50	P8	3
ONX	43	42	61G2343 486DX2-33/66 3	PB	4
OPX	45	46	52G9362 586-60 4	PC	4
OQX	--	44	92F0120 586-66  4	PE	4
OYX	--		06H3739 586-90  4	--	4

1  Also has 487SX processor (FRU P/N 92F0100) 
2  Also has 486 processor (FRU P/N 92F0147) 
3  Type 4 DX2-66 has 128K Level 2 cache 
4. Type 4 Pentium have 256K Level 2 cache.
5. 92F0145 is an Upgrade Type 1 486-DX2-66 with Flash Rom