I just picked up an Evergreen Technologies Spectra 333 processor upgrade at one of my favorite "computer junk stores" for $40. Here's what's really cool about it.
1) Its based on an AMD K6-II 333Mhz processor
2) It has a REMOVEABLE heatink with a 5v fan. The heatsink is kind of tall - but I've got a few old low-profile heatsinks around I can put the fan onto.
3) It has a stepdown regulator to get the voltage down to 2.2v. The regulator adds about 1/4" in height, so even with a low profile heatsink/fan I may still have to cut a hole in the case in addition to the RF shield. If so I'll probably just use the taller heatsink that came with it & let it protrude from the case for better cooling
4) It looks like the fan can be plugged right into the regulator. The fan leads have one of the 4 pin floppy drive type female power connectors on it and there's a 4 pin male header with the locking tab (that matches up with the floppy drive type connector) right on the regulator's PCB.
5) Here's the best part - the processor can be SEPERATED from the stepdown regulator. I had to start prying the processor out of the regulator's PGA socket a little bit at a time slowly and carefully with a thin-bladed utility knife until I got enough gap between them to use my old 486 chip extractor, but once I got the extractor on it the chip came right out. The reason that this excites me so much is that I already bought a K6-III 333Mhz. Since the K6-II and the K6-III are both marked for 2.2v core and 3.3v I/O I can't see any reason why the K6-III shouldn't just snap right into the regulator.
The regulator as some jumpers to set it up for a MoBo supplying anything from 1.8v up to 3.2v and a clock multiplier of 2x - 5.5x. The manual only mentions FSB speeds up to 66 Mhz, but I can't see any active components that might be frequency sensitive so I think it should be able to handle 83, 95, or maybe even 100 Mhz. If this turns out to be the case, it may even be possible to put in a K6-III 450Mhz or a K6-II up to 550Mhz.
I think this may be the best way yet to upgrade an I-O up to a K6-II (or better yet a K6-III) without any soldering. I'll report back on how it works in a couple of days once I've had a chance to give it a try (assuming anybody shows some interest).
Speaking of interest - anybody out there got a V4b or V5 (with the voltage regulator switch) who might be interested in buying a K6-II 333Mhz chip for a reasonable price? Hopefully I'll have one I want to sell in a couple of days ;)