CYRIX 333MHZ only performing at 266mhz

[ronnieg57]

can anybody tell me if a CYRIX MII 333 mhz MMX compatible can be overclocked ? right now it's only running 266 mhz compatible and I'd like to get it at least up to 333mhz or 350 if possible.

[Ape0r]

Look over your motherboard and through your mobo manual, there is probably a setting that is wrong if it is running 66 MHz too slow.

[Rugor]

The 333 in a Cyrix MII 333 isn't a speed, it's a Performance Rating. As I remember 266MHz is the speed it was designed to run at.

Cyrix considered it to have the Integer Performance of an Intel Pentium at 333MHz, hence the rating. Cyrix's old P-ratings despite being sold against P2's were based on the original Pentium.

[ronnieg57]

thanks for both replys. I've tried some different jumper settings on th mb and actually got it to perform at 299mhz (i believe, it was quite awhile ago) but it seemed to slow down even more!
as to rugors response that would probably explain why my Delta Force2 game give's me an error message (MMX processor not detcted) every time i start the game.
anyway, is there any way to overclock it (or maybe increase voltage setting to boost performance) or is this archaic old processor running as fast as it is capable?

TIA

[ukulele]

The Cyrix was designed to run at a higher bus speed (75mhz) as apposed to other pentium chips and AMD chips of the same vintage which ran a 66mhz, hence the higher pr speed rating. You may be able to push the fsb to 83 mhz on some boards, but I don't know about stability. I still have a cyrix 333mX computer that works but it has always been picky about drivers and apps even running at factory specs.

[Rugor]

Cyrix has two problems when it comes to gaming. The first is the notoriously weak FPU, and the second is the non-standard bus speeds. Cyrix ran on a 75MHz FSB with a 37.5MHz PCI bus, which often led to system wide stability issues.

To the best of my knowledge Cyrix is the only company that ever deliberately recommended running the PCI bus out of spec.

[jcsston]

I had the same thing. I bought a Cyrix MII 350, on the chip itself the settings were 83.3 bus, 3x which total 250mhz. My PCI bus ran at 41mhz with a PCI SCSI, TV tuner, 3d Video, and network card. My setup ran great until recently when my mobo died, a TX Pro chipset. I previously ran a Cyrix P166(133mhz) on that mobo.

[Stephen Soulsby]

Look in the "User to User exchange" section of this website. There is one guy right now that is selling K6-II 450Mhz and 500Mhz CPUs for $15 including shipping. If your current motherboard supports 100Mhz bus, pick one of those up before they're gone! Even if your board doesn't support that bus speed, get one and clock it as high as you can with your motherboard. I just got rid of a Cyrix MII 333 (83x2.5). Man did I HATE that CPU. Only 64k of cache total. For $15 you will see 2-3 times the performance of your current Cyrix. Not to mention that they run cooler (in my experience) and most of them can overclock my at least 50Mhz. The K6-II will fit right on your motherboard. Just make sure it supports 2.2v and 2.4v CPU core.

[Rugor]

That 64k of Cache on the Cyrix isn't quite as bad as it sounds. Remember that the chip uses socket 7 which is a fifth generation interface. So any L2 cache would be on the mainboard not on the CPU. So the 64k on a Cyrix is all L1, and compares very well to the Pentium MMX's 32k of L1 cache. The K6-2 only has 64k of cache too, unless you have the K6-2+ which is very hard to come by and has 128k of L2 cache onboard.

A K6-2 will be a vast improvement, but not because of increased cache size.