cjnston@pnet02.CTS.COM (Chuck Johnston) (09/05/87)
marb@sphinx.uchicago.edu (Marty Billingsley) writes: > > >I was recently asked this question and haven't been able to find a >good answer: > >Is there any way to change the clock speed in an IBM PS/2 model 30? >Either a hardware or software solution would be acceptable. >The problem: the PS/2 runs at 8 MHz and so software (games, educational >programs) that was designed to run at 4.77 MHz is too fast. (I guess the >guy who asked me this question is a frustrated asteroids player) > >It has been suggested that he could program the 1C interupt, which is >called every now and then by the OS (18 times/sec?), to delay for a set >ammount of time. Does anyone know how to do this??? > >Does anyone have any other suggestions??? > >Please send email, and I'll post a summary. Thanks! > > >Marty Billingsley (marb@sphinx.UUCP or marb@sphinx.UChicago.edu) > >---------------------------- >| SD (standard disclaimer) | >---------------------------- There are several public domain programs available to slow down turbo XT's for games and such, they are usually very short and I would upload one if someone could explain this ENCODE DECODE format to me. Now for my question, I recently installed an 8087 in my Epson Equity I (a standard 4.77 Mhz clone) and thought that since I had to rip the would thing apart to do so, I would give it a complete lobotomy and change the processor to a NEC V20. Well, before the change it had an expected Norton SI of 1.0. Afterwards it registered a 1.8!! At first I thought this was due to the 8087, but no, the real XT's at work still get a 1.0 with 8087's. Can anyone explain this phenonema?? Should I pop a 10 mhz chip in and see what happens?? UUCP: {hplabs!hp-sdd!crash, seismo!scgvaxd!cadovax}!gryphon!pnet02!cjnston INET: cjnston@pnet02.CTS.COM
dboyes@uoregon.UUCP (09/07/87)
The reason that you see a .8 or so increase in the Norton SI rating after installing a V-20 is that although the NEC chip is doing exactly the same things with the instructions in your program, the chip architecture has been streamlined to a great degree, thus making the processor more efficient. You're still running at only 4.77 Mhz, but the V-20 is making more efficient use of the cycles. BTW, the 8087 will only affect programs that use it, i.e. heavy floating point & transcendentals. Try compiling anything that does graphics (use QuickBASIC on the programs that come on the DOS supplemental disk) with the 8087 support and compare -- it's much nicer on the 8087, especially when circles are involved. -- David Boyes ARPA: 556%OREGON1.BITNET@WISCVM.WISC.EDU Systems Division BITNET: 556@OREGON1 University of Oregon Computing Center UUCP: dboyes@uoregon.UUCP