rhl@computing-maths.cardiff.ac.uk (Robert Hartill) (11/02/90)
I'm currently comparing the intel iAPX 286 and 386 processors with the view to writing a real-time operating system in protected mode. I've come accross an article which comes to the conclussion that a '286 is as fast as a '386 (with same clock frequencies). What are the highest clock frequencies in use for these processors ? I'm not interested in special cases where a some huge clock speed has been achieved in a test, etc. -- What kind of performance improvment can be achieved using with the fastest 386 clock frequency relative to the fastest 286 ? Any comments, suggestions, references that any of you think might be of interest to me will be appreciated. Thanks, Robert Hartill
davidsen@crdos1.crd.ge.COM (Wm E Davidsen Jr) (11/02/90)
In article <1990Nov1.165539.1359@computing-maths.cardiff.ac.uk> rhl@computing-maths.cardiff.ac.uk (Robert Hartill) writes: | I've come accross an article which comes to the conclussion that a '286 is | as fast as a '386 (with same clock frequencies). Would you believe both true AND false? For 16 bit instructions this is essentially correct. Actually there are a few instructions slightly faster on one or the other, but for MS-DOS that's about true. When using the 32 bit instructions, even with a 16 bit bus and SX chip, the speed of processing the 32 bit data goes up by about a factor of two. So the 286 is not even ballpark close. | What are the highest clock frequencies in use for these processors ? | I'm not interested in special cases where a some huge clock speed has | been achieved in a test, etc. I believe the fastest production 286 is 20MHz, SX is 20<Hz, DX is 33MHz. Intel talked about a 40MHz 386 at one time, but I can't recall ever seeing a product committment. Note that the 486 is about 2.6 times faster than the 386 for most things, because the clock counts for almost all instructions have been reduced. -- bill davidsen (davidsen@crdos1.crd.GE.COM -or- uunet!crdgw1!crdos1!davidsen) The Twin Peaks Halloween costume: stark naked in a body bag