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G4 single core 1.25 processor to dual core upgrade advice

B

Bru90

macrumors newbie
Original poster
Apr 6, 2014
23
1
London. UK
Hi... This is my first post.

Bought a G4 off ebay last week and from what I can gather it has the single CPU 1.25ghz and is the mdd model.

I'm wanting to upgrade the processor to at least a dual 1.25ghz as I thought this was that the machine came with as standard. I was ignorant to the existence of this last run of the line 'basic' G4 for booting into os9.

I've read countless posts on various websites and I'm really stumped on how to go about this.

If I get a dual core 1.25/1.42 off ebay from another G4 will it be a straight swap?

I know there are other aftermarket processors which will work such as the sonnet encore 1.3/1.6 but I'm confused about whether they will work with 10.5.8 which I want it eventually upgrade to and there was something about having to use another machine or hard drive to be able to install these processors.

Sorry it's a lot of questions for what is probably a very simple question.

I've found a dual core 1.25ghz CPU on ebay out of another G4 in the uk for a cheap price and want to get it but being such a novice I don't want to end up wasting my money on something which won't work :(

Some advice in layman's terms would be much appreciated. Thanks in advance !

B
 
You can swap the CPU board for any of the following Apple OEM ones:

Dual 1.0
Dual 1.25
Dual 1.33 (out of an XServe - this is what I use in my MDD G4)
Dual 1.42

This requires no hardware modifications.

I'm not sure what heatsink you currently have, if it's the one with many thin plates then you'll be fine for any of them apart from the Dual 1.42 (you really need the copper one with the heatpipes for this). If you have the other (aluminium?) heatsink with the fins, you'll want to upgrade to one of the other two types.

You can find the best prices for CPUs by putting the Apple part number (820-1470-A) into an eBay search. This is how I found my Dual 1.33 module for about £30.
 
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So if I grab the 1.25 ghz dual processor it will just go straight in ?

Happy days !!! Erm I've no idea what the heat sink is. Is there an easy way the tell the difference ??

I was planning on getting one or two pci fan slots - would that work instead of replacing the heat sink?? Sorry for the silly questions but I'm pretty excited to get my first mac and I don't want to break it :(
 
It can be made to work - you'll need to cut away part of the heatsink using a hacksaw to make room for the extra inductor that's on the dual processor modules. It would also be a good idea to add some extra cooling fans.
 

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I'm fairly sure that heatsink isn't the right one - it needs to be one of the Apple OEM ones. Just keep looking on eBay for 'Power Mac G4 heatsink', they do come up for sale quite often. They usually go for about £10 - in fact a few months ago one of the copper ones was sold for £14 (wish I'd seen it! :rolleyes:)
 
Ok super. Sorry for so many questions.

So if I grab a copper heatsink oem that will fit straight into my g4 and then I can easily install the 1.25/1.42 dual core processor without any hacking or extra fans ??
 
That's right. The copper one is the best, but also the most uncommon. Neither require any modifications to work, just apply new thermal compound and it will work.
 
Ok brilliant.

There's a dual core one on at the mo so might grab that and upgrade it to a copper one later.

I assume the old thermal compound will still be on the part and I just need to remove it and re apply ?

Thanks
 
That's right, the old thermal compound has probably more or less dried out anyway, so cleaning it off should be really easy. Most people, myself included, would recommend using Arctic Silver 5 compound when you fit the new processor - it's really easy to apply and keeps everything nice and cool.
 
That's great. Seems a lot easier than I expected.

Another quickie. Is this the correct CPU that I require. It has a different serial no to the one you recommended. It's a 1.25 ....couldn't find a 1.33 which is in your machine or is that a sonnet CPU?

http://bit.ly/PB2rbB
 
That one will work fine in your G4 -it even has the correct component layout to fit on your existing heatsink as well - buy it quick!

My CPU is an Apple original one, but it's not from a Power Mac G4, it's from an XServe server - both machines shared the same CPU modules.
 
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