back in the super 7 days, my friends and I all ran some sort of K6.... all of them were stable as long as you didn't overclock them.... if you want to overclock, you better get a huge heatsink... these CPUs run very hot, so a big heatsink is recommended regardless. I got the biggest one available for my K6-3 450 at the time and it was big enough that I had to cut a piece of the hard drive mounting bracket off to make it work! Many heat sinks of that era still aren't as big as what you see from the P4 or athlon 64 days

the K6s are very good socket 7 CPUs and are generally the fastest available due to raw clock speed. Their FPU performance is dismal though and even a very fast K6-2 or K6-3's FPU will probably equal only a P233 or something like that... so in this regard, the P2s were better than a K6-2 but were much more expensive back in the days and harder to overclock.... this is why the K6 series were very popular among hobbyists back in the days as shear clock speed was still better overall than the much slower P55Cs

the FIC VA-503+ is a very good motherboard... was one of the best super 7 boards made... I got one sitting here with a dead K6-2 in it, not sure if the board still works or not.... my friend killed the CPU when the CPU fan died

there's no reason to go more than 256MB RAM... win98 performance will totally suck once you have more memory than that due to its crappy memory management system... everything from that era runs plenty fast with 128 or 256MB

I went from a 166mmx to a K6-2 500mhz in 2000 and K6-2 pwns the P1 MMX anytime by a mile.

Reputation for stability problems mostly caused by unscruplous vendors selling overclocked systems (multis are unlocked on K6s), abundance of shitty motherboards and poor cooling.

Runs hot, but no need for psycho heatsinks- a celeron or p3 sink should be up to the job. On a good board, say P5A with a p3 heatsink or something and 128/256mb ram- this thing should be about on par with a P2 in speed and stability, with somewhat lower fpu performance of course.

yup... the K6s had a big problem with relabeled CPUs for a long time.... the scam artists would rub the labeling off the top of the CPU and put a new one on!

a big heat sink will still be good for long life of course.... a 2" tall heatsink is plenty for a K6.... it's big for socket 7 standards

The K6-2's and K6-III's produce relatively lots of heat for their days, but they were never real space heaters.
According to this site http://mysite.verizon.net/pchardwarelinks/elec_pentium.htm the K6-2/500 gave off about 21W. Compared to the Pentium-233 MMX (17W), Pentium 2 450 (27W) and Celeron 500 (27W), the K6-2 family actually ran quite cool!

The main problem when talking about k6-2, speed and overclockability is that:
1)they couldn't be clocked much higher then that, they were approaching their design limit.
2)their performance didn't scale very well above 500Mhz, so even a successful overclock didn't help improving performance anyway
3)most SS7 boards have stuff in the way around the CPU socket, preventing the larger coolers from being installed in the 1st place.

If you want maximum performance for SS7, then the K62+/K6-III+ are the way to go!
1)They run cooler (about 16W @500Mhz)
2)No issues with cacheable area
3)They can clock somewhat higher and perform somewhat better at very high speed compared to K6-2 (though not by much, but an improvement is an improvement, right? 😉 )

Most of the Pentium Pro models run hotter than any K6 😁

Obviously K6 was popular because it was so cheap.

Ok that answers several questions and raises 1.
If I understand correctly the K6-2+ was actually a mobile processor, would it still sit in the same socket as a K6-2?
Also if the CPU is labeled correctly it's the AFX version so I should be more careful with the cooling unit. The one attached is only about 1 inch high and has what looks like a 60mm fan on it (I'm just guessing here, I didn't actually bother to measure it). When I POSTed it, the heatsink was cool enough to touch, so I'm hoping it's good enough for when I run it under load.

Usually the voltage is written on the K6 heatspreader. The 2.4v units are basically factory overclocked slower 2.2v units.
The K6+ usually come in standard Socket 7 package.
Heres a couple examples:
http://www.cpu-world.com/CPUs/K6-2/index.html
http://www.cpu-world.com/CPUs/K6-III/index.html

The only issue may be that you might need a BIOS upgrade for the BIOS to correctly recognize the K6+.

Patched (hacked) BIOSes with better K6-III or the + CPU support:
http://web.inter.nl.net/hcc/J.Steunebrink/k6plus.htm

Plus chips really only need minimal cooling. Very slow 50-60mm and a basic heatsink is enough.

Well, I discovered what everyone ment by "lack of stability with K6 CPUs". Apparently Windows 95b will not finish its install with the K6 CPU, so I'm switching to a Pentium 233 MMX to install and then add a patch from Microsoft to fix the little problem. I guess this is a relatively rare problem with K6 processors, so I'm just lucky. 😉
That said, I might as well update on what I actually have in the computer (that's working so far):
10 GB 5400 RPM HDD (nothing stellar, but I don't need 10k RPM or a SSD with vintage systems)
LG DVD "super multi" drive (yeah I know it's not vintage, but it works and it was just laying around)
TEAC 3.5" floppy drive (hey, you can't knock TEAC, they're pretty decent)
Diamond Viper Nvidia TNT2 32MB V770 AGP 4x (sure beats my ATI)
Crystal Sound Card ISA (I really don't know much about it)
128MB x2 PC133 RAM (sticking with 256MB because of what TheMAN said)
400W Athena AT PSU (no comment necessary)

Windows 95 is installed and works but I was surprised to find that it's actually 95c not 95b as I had thought. At least there was good news after having to go through so much headache to get it set up and then even having to piece the heatsink back together after fixing it. 😁
Guess I'll post in the System Specs after I finish tweaking it.