Got a picture of the top?

It’s possible it’s a normal ceramic 166 but with that copper plate glued on.

Might be a chinesium jobber converting a laptop chip to descktop use.

Without giving it a closer look no idea

rmay635703 wrote on 2025-10-08, 20:24:

Got a picture of the top? […]
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Got a picture of the top?

It’s possible it’s a normal ceramic 166 but with that copper plate glued on.

Might be a chinesium jobber converting a laptop chip to descktop use.

Without giving it a closer look no idea

Well, at least according to my records, the SL27K is ceramic, so could be ...

wiibur wrote on 2025-10-08, 20:22:

Does anyone have info on these types of Pentium MMX 166MHz SL27K processors I've seen on eBay? They have a large copper heat spreader. What systems are these pulled from? Does that IHS sit at the same height as the typical nickel-plated copper ones, and would there be any specific heatsink requirements? Is it attached to the die?

It appears to have emerged from the disassembly of some very specific device, such as an oscilloscope or other advanced (for those years) measuring or industrial equipment.

yeah was gonna say, it looks like some industrial do over

Here are some pictures of the actual CPU.

Judging by the thermal pad imprint, heat should have been transferred to the device's case. The IHS simply filled the empty space.

Looks like a good idea.
A Standard socket-7 heat sink with fan should be able to fit directly on top.
Just add some thermal paste.

Might actually be a better idea for an AMD k6 and Over clocking.