right now my system has a K6-2/500 in it. it can support a K6-2/550 so i bought one. after installing it, applications closed/crashed unexpectedly and i was getting many Windows STOP errors. is this because i need to reinstall the OS for the new CPU? i was thinking this wouldn't necessary since they are both K6-2's and so have the same ISA. i bought the K6-2/550 used, is it possible it is defective? i made sure to re-set the (2) switches on the mobo for the proper CPU/speed and core voltage, respectively. the system freezes a lot with the current K6-2/500, so i thought i would try to upgrade the CPU to see if that helped. but i've just read in other threads that the K6-2's get quite hot and aren't that great for overclocking. i don't have it overclocked and frankly i'm not interested in that as i value the life of my CPU's. but it made me think that the K6-2's aren't very stable even without overclocking? the system can support a K6-2+ and K6-III, would it be better if i bought one of those types? if i get one of those, will i have to reinstall the OS? i would like to avoid reinstalling the OS, if possible. thank you.

Upgrading from 500MHz to 550MHz was a complete waste of money...hopefully you didn't pay more than $5-10 for the CPU? You'll never notice the 50MHz increase & probably could have overclocked the 500 that much without worry. Lockups are rarely caused by the CPU unless it's overheating. Considering it was doing it before & still doing after the "upgrade", I'd suspect the RAM. Download memtest86 & use the file to create a bootable floppy...boot off the floppy & let the program one for at least one complete series of tests. If any errors are found, determine which stick is causing it & remove it. Another likely problem is you've exceeded the cacheable limit of the motherboard chipset. Do you know what chipset the board is based on? The K6-3 is a better CPU due to it's onchip L2 cache, but the most common speed is 450MHz...too bad you're scared of overclocking, the 450MHz has been known to run at 600MHz. The K6-3 is "pricey" though...probably $40 or more. You never have to reinstall the OS after a CPU change. This space for rent

The K6-2 550 was one of the worst cpu`s there was---I had no end of trouble with them, as a routine I would clock them back to 500 and they were bulletproof. I imagine the 550 was at the end of the thermal limits of the design. Also if you want to overclock the k6III chips make sure you get the "+" cpu`s as the original k6III were very poor overclockers----Best bet for you would be a k6-2+ as they are less than the k6III and ran as high as 600mhz

well the ram is not a problem, as i also upgraded it with brand new Kingston ECC modules. i'll get back to you with the mobo chipset, as i don't have the manual right now. i think it was some sort of VIA, though. i don't ever have to reinstall the OS? even if i change to a completely different architecture like intel x86? how is that possible? the crashes and STOP errors only occur when the K6-2/550 is installed. the STOP errors mention IRQL_NOT_LESS_OR_EQUAL or something like that. i think the STOP error was 0x0000000A. since i won't have to reinstall the OS, i'll just look into a K6-III or K6-2+

AMD k6-2's were the processors that put AMD on the map and gave intel competition on its Pentium 2 series. K6-2 would have been great if it had L2 cache, but considering it didn't, it was a short lived chip in terms of preformance. AMD Athlon 64 X2 4200+ 2GB Dual Channel DDR 3200 Nvidia 6800GT SATA II 250gig 7200rpm 8mb cache Gigabyte Nforce 4 SLI

"i don't ever have to reinstall the OS? even if i change to a completely different architecture like intel x86?" I didn't say that! But if all you're doing is upgrading the CPU & not changing the motherboard, nothing has to be done with the OS. "i also upgraded it with brand new Kingston ECC modules" I would you buy ECC RAM? http://www.microsoft.com/resources/documentation/Windows/XP/all/reskit/en-us/Default.asp?url=/resources/documentation/Windows/XP/all/reskit/en-us/prmd_stp_hwpg.asp This space for rent

OK well it is obviously the new CPU that is the problem. I got a refund so don't worry about my money anymore. Since i'll be using the old K6-2/500 for now, is there anything i can do to reduce or even prevent the system from freezing up? i am pretty sure it is the CPU that is causing the problems, but i am open to your ideas. the freezing has been occurring for a long time. it was happening back when the system was using windows 98. the system only freezes after being on for several days. it works fine again as soon as i hard reset it. no new hardware has been added (except for new RAM, which hasn't changed the behavior).