Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!utgpu!water!watmath!clyde!rutgers!psuvax1!vu-vlsi!cbmvax!daveh From: daveh@cbmvax.UUCP Newsgroups: comp.sys.amiga Subject: Re: 68020/68881 on A2000 Message-ID: <2858@cbmvax.UUCP> Date: Tue, 24-Nov-87 23:58:57 EST Article-I.D.: cbmvax.2858 Posted: Tue Nov 24 23:58:57 1987 Date-Received: Sat, 28-Nov-87 13:14:08 EST References: <1718@netsys.UUCP> Organization: Commodore Technology, West Chester, PA Lines: 48 in article <1718@netsys.UUCP>, bathkey@netsys.UUCP (Scott Bethke) says: > Keywords: 68020 amiga B2000 68881 32 bit speed > > .. but I dont > believe this HYPE about 60 Hour Scuplts taking 45 minutes .. Also if only > a handfull of Amiga applications have to address the 68020 and 68881 directly > what good is a 68020 in my amiga? If anyone has any Serious speed benchmarks > and would not mind sending (email) them to me, please do so. Id love to see > the difference I'm not sure if Sculpts really go THAT fast, but they do go quite a bit faster. On the Commodore-Amiga 68020 board that I'm currently working on, we get maybe a 25x increase with Sculpt. But that's a Sculpt compiled for 68020 and coded with in-line 68881 instructions. Part of the lack of speedup on generic things is the state of the current math libraries. The best thing to do for better speedups in the floating point department is (A) hope that your turbo board supplier has a set of libraries written for the 68881. This will make everything that uses the libraries much faster. The next release of the Amiga OS will include math libraries that support the 68881 very nicely, but for now it's up to the third parties. The other part of the picture is CPU bound stuff. While the 68881 can boost floating point performance from 25x-100x depending on what you're doing, the 68020 itself out of fast, 32 bit RAM is more like a 4 times speed increase. That, of course, assumes that you have this RAM where the OS can get at it. How does CSA configure their 32 bit RAM? If it's not at the head of the FAST memory list, you may be getting other memory first. If it's autoconfigured, you definitely want to run SlowMemLast on a B2000. If not, that may or may not put the 32 bit RAM up front, depending on their AddMem command. Should be really noticable if it's wrong vs. right. And finally, you're not going to see much of a speedup on anything that's display bound, as you probably expected. We're supposed to have a mandelbrot program around that shows off the '881; if I get that, I'll send it along. Just a demo, but should at least give you an idea of the speed increase. > Scott Bethke, BATHKEY AT NETSYS.UUCP > > {decvac, esi, ihnp4, killer}!netsys!bathkey > BBS Number 301-445-3777 Voice Number 703-866-9122 Dave Haynie Commodore-Amiga Usenet: {ihnp4|caip|rutgers}!cbmvax!daveh "The B2000 Guy" PLINK : D-DAVE H BIX : hazy "I can't relax, 'cause I'm a Boinger!" -- Dave Haynie Commodore-Amiga Usenet: {ihnp4|caip|rutgers}!cbmvax!daveh "The B2000 Guy" PLINK : D-DAVE H BIX : hazy "I can't relax, 'cause I'm a Boinger!"