Path: utzoo!utgpu!watmath!clyde!att!rutgers!mailrus!eecae!cps3xx!rang From: rang@cpsin3.cps.msu.edu (Anton Rang) Newsgroups: comp.sys.mac Subject: Re: Mac II processor upgrades Message-ID: <1248@cps3xx.UUCP> Date: 6 Dec 88 21:09:56 GMT References: <65023@ti-csl.CSNET> <3356@ucdavis.ucdavis.edu> Sender: usenet@cps3xx.UUCP Reply-To: rang@cpswh.cps.msu.edu (Anton Rang) Organization: Michigan State University, Computer Science Dept. Lines: 34 In-reply-to: ecs175f037@deneb.ucdavis.edu's message of 6 Dec 88 16:59:19 GMT In article <3356@ucdavis.ucdavis.edu>, Greg DeMichillie (lgdemichilie@deneb.ucdavis.edu) writes: >In article <65023@ti-csl.CSNET> holland@mips.csc.ti.com (Fred Hollander) writes: >>I heard that there is a 68030 replacement for the Mac II that runs at 33MHz >>for about $1000. First of all, how can the processor run faster than the >>rest of the motherboard? >The processor would have to have several wait states for each Nu-Bus access >since the bus is only clocked at 10MHz :-( The 68030 replacement must be on a separate board, I would guess. If it has a reasonably large cache (say, even 8-16K) there wouldn't be too many NuBus accesses (hopefully). There would indeed be several wait states for NuBus access, but this wouldn't occur that often. >So, some operations will certainly be much faster with the upgrade, don't >expect everything to suddenly be twice as fast until Apple upgrade the Nu-Bus >to operate at higher clock speeds (a la Steve Jobs' NeXT) Of course, the NuBus standard is 10MHz; so no standard NuBus cards would work with one running at a higher clock speed. The cache ought to give pretty good performance (remember, there are lots of large computers with slow memory). A graphics coprocessor (to reduce the amount of cycles spent waiting for video memory updates) would help a lot, too. Anyone for designing a custom QuickDraw chip? (Or a microcoded Display PostScript interpreter, even? :-) Anton +---------------------------+------------------------+----------------------+ | Anton Rang (grad student) | "VMS Forever!" | "Do worry...be SAD!" | | Michigan State University | rang@cpswh.cps.msu.edu | | +---------------------------+------------------------+----------------------+