Overclocking Your iBook to 600MHz

Cryptnotic writes: "The guys at Accelerate Your Mac have figured out how to modify the motherboard on the recent Apple iBooks to get them to run at 600MHz with a 100MHz bus speed. There are benchmarks comparing the OC'd iBook to some regular Apple desktop machines. However, what I am wondering most is how this overclocked G3 compares to the much more expensive Apple G4 Powerbook and if it makes it worth voiding the warranty." Remember, not recommended for your iBook.

Comments

Re:Benchmarking battery life

[Mwongozi]

Perhaps if you had read the article, you would have seen this:

Battery life at 600/100 is about 15-30 minutes less than 500/66 ...and when the speed is switched down to the 350/100 setting, I get better battery life than I did at 400/66. Additionally, DVD playback is still smooth at 350, so I can actually get MORE DVD playback time than before.

Apple, marketing and processor crippling.

[irn_bru]

The G3 has been around for ages. It has long been suspected that the speeds chosen for use in iMac and iBooks are conditioned more my marketing factors then technological limitations, particularly the 66mhz system bus. Basically, IBM can clock them faster the Motorola can clock G4s, but it is unacceptable to have a faster chip in the cheaper machines (Altivec excepted).

The 3-5 degree raise in temperature seems entirely within the engineering limitations of the machine and I have to say that this mod looks very enticing indeed.

Re:Apple, marketing and processor crippling.

[Graymalkin]

According to IBM's datasheets on the 750CX and CXe (the iBook uses a 750CX IIRC) they can use up to a 10x multiplier and a 133MHz memory bus. Theoretically IBM could spit out 1.3GHz G3s if it ever needed to. The problem with mere speed bumps on the PowerPC line is EOL concerns. The G3 750 and previous models had 60x pins and thus were compatible with older systems but the 750CX has none of these and is only compatible with more up to date systems. Thus making G3 chips for the system upgrade folks like Sonnet wouldn't bring in good returns for either company since the upgrades would only work on relatively new systems where a fair percentage of chip upgrades go into EOL Apple products. IBM, Mot, and Apple all need to keep their eyes on the future too. The G4 is able with little modification to use 64-bit instructions and a 128-bit memory bus width. The G5 will have that stuff by default so most likely Apple's going to go full fledged 64-bit Weapon X style (10.2 supposedly will come in 32 and 64-bit flavourings while >2 will be 64 bit only). That'd mean keeping the older G4 around for the low end systems and going with the G5 in the high end systems or so I surmise. I don't really see it as processor crippling but more like Apple has a much better sense of where their processors are going and what is happening with them. They're much more involved than the PC OEMs that just buy crates of whatever Intel happens to be making at a particular time. It's too bad no one will pick up the G3 to ramp the speed up to super fast levels. I really like that chip.

NOT recommended!

[Bud]

I performed the 600/350 modification to my iBook three weeks ago and IT DID NOT SUCCEED. When I had assembled the iBook again it wouldn't boot up. So I had to open the case again and move the resistors back. Luckily it works again. :-) Sturdy little bastard... Considering the amount of time I spent on planning and double-checking the mods, I can only assume that there are errors on the web page. I did the mods by hand, soldering very carefully and checking the result with a multimeter afterwards.

Another note: It's impossible to open the case without making ugly marks. You need at least three hands and several thin but nonflexible steel blades. Having done it twice (once for modding and once for demodding), I'm considering opening it once more in order to file down the ugly edges -- and repaint the inside in ultramarine blue. :-)

The only positive thing is that I now know how to replace the optical drive and hard disk. 10GB doesn't really cut it nowadays... I would really like one of those 48GB drives.

That's my 0.02 euro. And... if someone actually succeeds in performing the 600/350 mod, please let me know exactly what resistors you moved. :) Pleeeease!

--Bud

Re:NOT recommended!

[Rogerborg]

• I can only assume that there are errors on the web page. I did the mods by hand

Ah, I see your problem. Read this page carefully:

• "ugh, it looks as if I soldered it with my feet"

just for future reference

[4444444]

you should never use a mutimeter to test resistenc ein a circuit. 2 reasons for this are you are not mesearing the resistence of the resister you are mesauring the resistence of the hole circuit the resister is in. second reason multimeters in the ohms setting puts out a current to do the measuring and depending on what you tuch you could possibly fry something

Re:My Mac laptop

[hattig]

Why buy something that's not the latest greatest?

Because the latest and greatest costs a whole lotta money, whilst 10% slower is half the price?

Buy the most RAM you can afford

Agreed.

Buy the fastest machine you can afford

Disagreed. Buy the fastest machine that will handle your needs for today and the next year. After that time even the most modernest of machines today will look like it was made by Ug the caveman anyway - lets not spend too much money on it!

The iBook is a great buy for students and for general portable work. However, I am still doing fine with a PII 266MHz laptop (HP Omnibook 4100) and feel no need to upgrade it yet (still running Win 95 and Office 97 [and Linux]). Hardware only needs upgrading when you buy the latest software for marginal benefits!

Remember - RAM, HD and CPUs will be even cheaper in a year's time. By buying cheap (but sensibly, don't buy an out-of-date platform like KT133 or i815!) you can buy cheap again in a years time and double the performance of your system (then sell the replaced parts on eBay). Whatever, always buy the best motherboard possible! That is the most important part of the computer.

And now I see that Slashdot has messed up again and everything gets me onto the front page without a login. I mean, none of the Slashdot bugs are being fixed at all, and they have had plenty of time since the release of 2.2...

Titanium Chef

[Ukab the Great]

You know, if you overclock the all-metal PowerBook G4 to a fast enough speed, put a piece of cheese in between two pieces of bread, and slam it shut between the lid and the handrests for about 5 minutes, you could make a really awesome grilled cheese sandwich.

Successful mod done.

[pinkpineapple]

The article on xlr8yourmac.com is quite old, so I am quite surprise about the big fuzz that it generates today on '/.'.

I applied the mod about a month ago, when I decided to invest into a decent and not too expensive Linux laptop. I was quite happy with the speed of the machine, but heard from a friend of mine who knew someone at Apple who told her that the machine was originally designed for 100MHz mem bus. The only thing that required Apple to move back to 66MHz was to be able to give the machine a four hour battery run as the marketing brochures showing these figures were already printing when the tests were being ran (!)

With this in mind, I just overclocked the memory bus of the machine, because I believe that it is the main bottleneck for my application of the iBook: basically watching a DVD, playing MP3 files with iTunes (great player by the way) and being able to type a report for my boss at the same time. Yes, I can do that, but the laptop had some troubles keeping up ;-)

There are a few catches though. Part of the RAM is located on the motherboard (64MB or 128MB depending on the model you get) and the memory controller would need to be reprogrammed in theory. Not doing so can will cause some RAM not to function properly and that could be the reason for the mod not to succeed. The other problem is having the speed bus directly encoded in the OpenFirmware ROM (kinda like a BIOS thing on PC.) You can patch the value by adding an extra Forth patch in non-volatile RAM, so it's ok. This is required for some OS to calibrate properly. In my case, that didn't matter because the CPU bus was the same.

Doing this mod, I ended up using the same number of resistors. I just add to move them around. If you go for another config and end up using less resistors, keep them in a safe place as you never know what is going to happen (some people want to purchase only genuine speed laptops, so you may want to revert the mod if you sell your laptop in the future.)

I didn't add the extra metal plate as it is described in the article, because I didn't want to create to much pressure on the components or get a bended keyboard (which would have made the keys touch the screen as on the TiBook.) I just added some clear heatsink paste (the one that doesn't get messy.) I never had a heat problem with this machine, before or after the mod, even under Linux. Linux kernel is not really energy savvy on the PowerPC at this time (some bugs and lots of hacks to get the fastest context switch doesn't goes along with good energy saving.)

The last point I want to cover, is that you need to make sure you are really careful about disassembling and reassembling the unit. Aesthetic is a big thing on this particular brand of machines, so don't mess with it. I used a soft flat spoon (the kind you can find at your supermarket for mixing stuff with soft flat edges) to lever the side of the machine. I also used surgeon gloves during the all operation (no pun) and worked in the kitchen area the only place without carpet in my house. I touched the fridge before putting the gloves to make sure I didn't carry any static. You are never too careful and because this mod voids the warranty you may want to think again before going for it.

-- PPA