First post, by megatron-uk
I have been offered a lovely little Olivetti PCS 11 desktop... it looks to a very small LPX implementation, barely taller than a 3.5" floppy and single slot ISA card.
It appears to be in really nice condition except a broken power supply. However, it's the absolute bottom of the barrel 386SX-16 model.
I'm interested in desoldering the QFP processor and replacing it with something a bit better; I could do a 386SX-25, which the board was equipped to handle, but I'm thinking about possibly one of the available QFP-100 format upgrades - I think it comes down to the following options:
- Cx486SLC / Tx486SLC: 1KB cache, 5v tolerant, 20 to 40MHz parts.
- Tx486SXLC: 8KB cache, up to 40MHz.
- Tx486SXLC2: 8KB cache, clock doubling (20, 25, 33MHz input) for 40 to 66MHz parts.
- IBM 486SLC: 16KB cache, 33MHz.
- IBM 486SLC2: 16KB cache, clock doubling (25, 33MHz inputs) for 50 and 66MHz parts.
My understanding is that the Cyrix and Ti cores are identical, just like the DLC versions, but that the IBM SLC core is entirely different and derived from Intel. However, that's almost entirely irrelevant as the availability of IBM SLC processors appears to be virtually non existent, whereas the SXLC and SXLC2 processors are much more common - though finding 5v rated parts is a little harder.
Are all the above options pin compatible with the 386SX? Anyone have a success story to share relating to swapping out a surface mount 386SX with one of them?
I did buy one of those old stock Kingston 486 Now! IBM PS/2 model 50 upgrade cards many years ago and never found a use for it - it has a 50G6950 marked 486SLC2 on it, but I've had a hard job finding specs on it. That's a possible option....
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