Boosting an LC III from 25mhz to 33mhz, is it worth it?

#1 Sat, 10 Sep 2011 - 02:24

I was reading up on overclocking my LC III (using this guide here), and was wondering if it's worth it to do this modification to it. I'm thinking about installing OS 8.1 on it and figured that the speed boost might help it a bit.

It has 36MB of RAM installed and a 1.2GB SCSI drive.

So what are your thoughts on it? Have you done this mod to your LC III? Was there a noticeable performance increase?

#2 Sat, 10 Sep 2011 - 03:56

I didn't realise it was that easy to do - just remove one resistor sounds like a nice way for free Mhz to me! Go for it, I say

#3 Sat, 10 Sep 2011 - 14:25

Go for it, 030's are fairly durable though to be on the safe side it wouldn't hurt to stick on a little heatsink.

#4 Wed, 12 Oct 2011 - 01:05

Considering Apple sold 33MHz LCIIIs (known as LCIII+s by most and housed in an LC475-type case), it's probably the safest upgrade out there.

#5 Fri, 2 Dec 2011 - 09:13

Yes it is worth clock-chipping, and your LCIII will be faster.

#6 Fri, 2 Dec 2011 - 15:31

I'd say to hack in a little circuit using the existing resistor, some wire wrap and hacking a header jumper from it to the power side to make an easily activated test circuit so it'll be easily reversed for doing some benchmarking. It'd be very interesting to see how it runs the two systems, clocked at both speeds.

I've got a pic somewhere of the incredibly fugly hack I did like this on the DuoDock's DeclROM power leg if you're interested.

#7 Sat, 3 Dec 2011 - 18:59

I've made benchmark comparison my LCIII and LCIII clock-chipped to 33Mhz, can post it here later.

#8 Mon, 26 Dec 2011 - 00:16

This little hack works very well. You might go even a little further: consider to add a MC68882 FPU. A while ago I ripped one off a dead PB 180 daughter board. If you attempt to take a FPU from a PowerBook, the use of a heatsink properly attached to the FPU is necessary (or you will notice a smell of boiling resin, soon). There are a few application programmes that need a FPU (no software FPU emulator), like DraftBoard.

Note: The LC III supports the excellent Portrait greyscale monitor (as opposed to the LC 475). It makes a nice machine for drawing, text and layout work.

#9 Sun, 29 Jan 2012 - 05:12

Is there a version of this hack for the LC520 board, which is supposed to be exactly the same except rearranged to fit the all-in-one case?

#10 Sun, 29 Jan 2012 - 11:08

No. See: http://homepage.mac.com/schrier/mhz.html