ok, on p2's here is the scoop
most p2 233's and 266's were completely unlocked but ran at 2.8v and could not overclock past 300 (outside chance at 333). your best bet is to put on on a BX motherboard and run them at 300 (3.0 x 100) or 309 (3.0 x 103)
most early p2 300's you could put in any multiplier up to 4.5, however, again, they ran at 2.8v and did not overclock very well at all, your best bet is to completely avoid this chip, it is the worst overclocker ever, except the p3 600 katmai
All p2 333 and up ran at 2.0v, and most overclocked well. Up till august 1998, all p2 333's you could set any multiplier up to 5.0, most could do 400 (4.0 x 100), some could do 450 (4.5 x 100) on BX boards, this was at a time when the best P2 available was the P2 400 which cost over $800... this was the best chip bargain until the 2.0v p2 300 came out
ALL P2 chips made after august 1998 were multiplier LOCKED
there were some VERY early p2 350 and 400 chips that you could unlock on some board which had the BSEL low/high trick in bios, but these chips are so rare it is not worth mentioning
OK, the P2 300 in steppings of SL2W8 (OEM) or SL2YK (retail) were excellent overclocking chips. They ran at 2.0v core and most could do 450 at default voltage, or close to it. Best overclock value P2 ever!! Also, there were a couple stepping P2 266's that ran at 2.0v and you could overclock them to 400 (4 x 100) or sometimes 450 (4 x 112) if your chip and motherboard could take it... I had 3 systems at the time with SL2W8 chips and BH 6's or BX6-2's which ran for YEARS at 464 (112 x 4.5) at default voltage. Also of note, these chips are multiplier locked as well...
some VERY LATE SECC2 Pentium II 350's will do 466 (3.5 x 133) very reliably and are faster than a p3 500, but at this point, its not worth messing with p2's to be honest with you
