No worrys, It seems their are a few active cyrix 5x86 topics so I'll continue to question in one of those threads.

To conclude

I bought a gainbery upgrade cpu, adapter thingy had broken pins, removed cpu which tested does work, purchased another which is fully functional running mainboard at 5V.

Stepping for both CPUS 05H.

I also have a green cyrix 100 heatsink version, also 05H, cant test this cpu fully as the mainboard runs only at 5v, I tried unscrewing the voltage regulator screw from the heatsink on the 2nd gainbery but I could'nt loosen it, I decided that breaking my wrist in rage punching a wall stud because I persevered in swapping 5x86's into voltage regulators was not worth it, the old saying "If it aint broke don't fix it!".

In conclusion, IT appears all blue IBM branded 100 cpu's will run at 120mhz or were good enough to, both my gainbery 120 cpus had a yellow sticker covering the IBM HF100 text on the heatsink, not sure what text is on the actual pga package.

This may not be a startling revelation, I had read on other forums that the IBM 100 was rumoured/assumed to be a cyrix 120 in disguise but from my expensive research I can safely conclude the IBM 100 will run at 120mhz without any trouble.