CompuServe Thread

Tim: The 1200MBX isn't a special machine, it's an expansion product sold by MicroBotics that adds a 68881 and memory expansion. It fits in the trapdoor on the bottom of any A1200. // -Mike Schiller \X/ AMIGA! On AutoPilot in sunny Fort Lauderdale

An MMU is a "Memory Management Unit" it used, on the Amiga, mainly to copy the kikstart ROM to 32 bit RAM to increase speed (Old 16 bit ROM's in A500's and A2000's is substantially slower than 32 bit RAM.) An MMU can also be used by a computer to handle "Virtual Memory" The Amiga OS doesn't support this type of thing yet (there is at least one 3rd party software package that does) However, in my opinion I don't want virtual memory on a home machine. I had a whole class dealing with this subject when I was in college, so if you want me to go into more detail, I will. Yes, the 68EC020 is a "little" faster than a stock 68020 with a MMU (68851?), but not all 68020 machine's have an MMU, it is a separate chip that the 68020 can use… The 68EC020 can't drive the same MMU basically becasue of it not being signal compatible with a 68020. Which in the A1200 class of machine, is no handicap, in fact, it's an advantage becasue of cost. The MBX1200 is just an expansion board the plugs into the belly slot of the A1200, and has a 68881 FPU chip on the board (as well as a SIMM socket, that I have 8 megs of 32 bit RAM in. Software has to be written to take advantage of the MMU (Any MMU on any Amiga) So It'll only speed things up that are written for it. The 32 bit fast RAM that I have added speeds up the whole machine though (about 75%) AGA and 68881 don't have anything to do with each other, older Amigas can have the 68881, or 68882, that's not a new thing. I almost bet that having an FPU will not speed up DPIV, but don't know at all— I don't have DPIV, though most paint programs don't use a FPU becasue of not needing one (any math they do is all integer math and an FPU doesn't help that.) I bought the MBX1200 mail order for about $150… 3's a tough question, but to say it simply yes if the processor and bus speed is the same, and the memory path is doubled. On the A1200, the path is double, the clock speed of the CPU is double, and the CPU is more <continued>

efficient than the 68000, hence around a 3 to 7 times increase in speed, depending on software, and availability of fast RAM. Yes, my tests were run with 68020 optimized code. If your A2000 is a stock machine with only extra fast RAM, you'd get around a ~5 times increase in over all speed, with a big increase in graphics speed. If you have an accelerator for your 2000, and depending on wich one, the A2000 would probably compete fairly well in iverall speed, but it can't match the graphics speed of the A1200. Animations should be smoother and the ability to do animation and sound should be better on the A1200 (not to mention MANY more colors available in any resolution!), becasue of it's AGA chipset, not to mention the @ meg of chip 🙂 The A1200 is such a great machine, I just GOTTA talk about it! 🙂 Bob Comer

DENNYA: FYI, the CompUSA outlet in Milwaukee (suburban Brookfield, actually) does indeed carry COMPUTE, but it doesn't have the Amiga Resource section. At least not when I checked; maybe they don't always ship the right version.

Thanks Denny, I'll call in the morning. Appreciate your response. ==Bob==

I felt the same way, but now I gotta get a multisync 🙂 Need it anyway for Links 🙁 Golf computer games are about the only games I play, and I was looking forward to it being faster… Still wouldn't trade my 1200 for all the computer golf games in the worl though 🙂 Bob Comer