Copied From The CyberNET BBS CLINK 911:6230/2.0 714-378-0085 item: 2 subj: 50mhz FPU on A3000 from: Oliver Rokoff on : Tue 1-Feb-1994 6:43p I recently read the following post on Usenet, though i haven't got the guts to try it out, it does sound interesting: *** Area: USE_HARDWARE Date: 11 Jan 94 13:15:50 *** From: Mike Noreen (92:901/231.14) *** To : All *** Subj: A3000 FPU run at 50Mhz successfully! I just thought I'd tell all A3000 owners something they might find interesting: I right now run my FPU at 50Mhz, and it works! I've been rendering a 30sting: I right now run my FPU at 50Mhz, and it works! I've been rerame animation for the last 24 hours to test the FPU, and sofar there's been no problems. The temperature in the room is 21 degrees centigrade, and the temperature of the FPU is still under 40 degrees (according to a thermometer I left in the immediate vicinity of the FPU), so there doesn't seem to be any heat dissipation problems. I'll continue to render for a few days more to make absolutely sure the FPU can handle the doubled speed. According to AIBB I'm 11-96% faster than an ordinary 25Mhz A3000 on floating point (I assume the differences depend on the amount of memory accesses done by different types of tests). In the beachball test (the interesting one) I'm 40% faster than a 25Mhz A3000. SysInfo claims that I'm doing 1.1MFlops, as compared to the 0.66 I did before the hack. The beauty of this hack is that it didn't cost me a penny. This is the way it was done (thanks to Stefan Johannesdal for telling me how to do it!): (continued next post) --- CNet/3 * Origin: Amiga's Alley (911:5050/1.0) Washington Hub Kent, WA 206-859-0525 14.4 HST (911:5050/1) End of item. Respond or Pass> item: 3 subj: 50mzh hack on 3000(cont.) from: Oliver Rokoff on : Tue 1-Feb-1994 6:45p 1) If you look at the motherboard from the front of the computer, you will see the FPU close to the front/middle of the computer. Locate pin 11 (it's the second from right on the far side of the 68882). From this pin a copper wire goes out then right, and then disappears down through the card on the right side of the FPU. This wire is the FPUCLor CLK30), and has to be cut (preferrably on the underside of the motherboard. It resurfaces one cm to the right of where it went down, and me and my more soldering experienced friend cut it between these two points). 2) Locate resistor R120 (22 ohm). It's just left of the 50Mhz crystal, and the far side of this resistor is to be connected to the FPUCLK pin of the 68882. We did it this way: we soldered a wire on the underside of the card from the point where the wire after the R120 goes through the motherboard, to the point where the FPUCLK wire from pin 11 went through the motherboard the first time. That's it. We tried to do it neatly, and to make it as hard to spot as possible for service technicians (I've still got warranty...maybe), but if that's not a concern you can simply solder a wire between R120 and the FPUCLK pin, after cutting the FPUCLK wire. The greatest problem was actually dismantling/reassembling the A3000... *************************************************************************** If anyone got any programme which tests the reliability of FPU's, I would GREATLY appreciate it if you'd UUencode and mail them to me! PLEASE! *************************************************************************** UUencoded AIBB module available on request. DISCLAIMER: I am not responsible for any errors which might have gotten into this post, or for any mistakes you might do when trying to repeat this hack, nor for any damage it might cause. It works for me, on my A3000, but there's no guarantee it will work for you. Don't try this unless you're absolutely sure that you can handle it. This hack pushes the FPU beyond it's specs, and might shorten the FPUs lifespan, and cause computational errors. I have no indication this is the case, but it is a definite possibility.