Installing 6GB RAM in early-2008 MBP - which slot for 4GB module?

Hi - I recently found out that the early-2008 MBP will (unofficially) actually take up to 6GB RAM using one 4GB module and one 2GB module. I currently have 4GM RAM (2 x 2GB DDR2 667Ghz modules), but do a lot go memory-intensive stuff (editing very large image files in Photoshop, running Virtual Machines etc., running games like Dragon Age Origins etc.), so would like to try out expanding the RAM and have just bought a single 4GB DDR2 667Ghz module (from Crucial, which is where I got the 2GB modules from, so should hopefully be compatible)

What I'm not sure about is whether this will only work properly if I install the 4GB module in a specific memory slot? I'm guessing the first slot would make the most sense, but I'm not sure. Has anyone tried this? Thanks

If it doesn't work, I can apparently still return the RAM to the supplier.

Mal said:

Either slot will work fine, they will not treat it any differently.

jW

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Okay, thanks for the info.

Okay, have now received my new Crucial RAM 4GB DDR 667Ghz module, I installed it in the most accessible slot on my early-2008 MBP i.e. the "top" slot (Bank 1) and I'm very happy to say that my MBP now recognises 6GB of RAM and seems to run a whole lot smoother, especially when running Virtual Machines and editing large files in Photoshop.

Bad news I'm afraid...

oxfordguy said:

Okay, have now received my new Crucial RAM 4GB DDR 667Ghz module, I installed it in the most accessible slot on my early-2008 MBP i.e. the "top" slot (Bank 1) and I'm very happy to say that my MBP now recognises 6GB of RAM and seems to run a whole lot smoother, especially when running Virtual Machines and editing large files in Photoshop.

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Unfortunately 3 days after I installed the 4Gb module my Macbook Pro wouldn't turn on (for more info. see here)

I then tried swapping back in the original 2Gb module, but the machine still wouldn't turn on. So I took it into a trusted certified Apple Service Engineer, who has tested the machine, this is his report:

"I have investigated your machine and found that the problem lies within
the main system logic board and in particular the memory slots. When the
ram modules are removed the machine stays powered on and emits the usual
beeps.

I have tried known good memory but this gives the same shutting off
scenario."

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He said that the only solution is to replace the logic board - the cost he quoted, including labour and VAT tax is just under £500, which is about what an equivalent model would cost secondhand on eBay (though mine is the slightly better and rarer 2.5Ghz variant). Am not sure whether to proceed with the repair or not...

Anyway I told him that I had installed the 4Gb module and he said that:

"it may have been the cause as the logic board does not take 4GB modules."

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So - although 1 x 2 Gb and 1 x 4Gb may work for some people in 2007/2008 non-unibody MBPs, it seems that this is a potentially very risky procedure, especially if your Apple care has expired (I had 3 years extended Apple care, but it expired 6 months ago, grrr....)

Mal said:

Sorry, but whoever that is is full of it. The logic board doesn't have a problem with the 4GB chips, and the chip itself could not have caused your failure. Either there was a static shock in the process of installing that damaged the memory slots, or there was a problem that developed either beforehand or afterwards, but just having a 4GB chip in there cannot cause any problems (other than immediate refusal to boot if the machine truly didn't accept 4GB chips). They would either work or not, not cause slow damage

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That's actually what I thought, and the machine did boot fine and worked for 3 days with 6Gb installed (in fact it seemed much zippier). Why would it then die 3 days afterwards, though? Its a bit suspicious that this happened so near the the RAM upgrade. If I'd caused static shock damage to the memory slots when upgrading, wouldn't the problem have manifested itself immediately?

If I do get it repaired, though, am not sure I want to risk putting the 4Gb module back though...