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has anyone here actually installed 3gb ram in a macbook? i'm not disputing the possibility of it. rather, i'd like some insight as to whether the performance increase is dramatic. anybody experience the wonder of a 3gb macbook?
 
OWC are the only ones claiming compatibility to this point - we will try it when we have a MacBook for testing. OWC wouldn't fake it, so I am sure they have it working -- what I don't know yet is whether this is some specific approach or whether a range of 2 Gb modules will work.

Thanks
Trevor
CanadaRAM.com
 
OWC are the only ones claiming compatibility to this point - we will try it when we have a MacBook for testing. OWC wouldn't fake it, so I am sure they have it working -- what I don't know yet is whether this is some specific approach or whether a range of 2 Gb modules will work.

Thanks
Trevor
CanadaRAM.com

You're the resident RAM expert :D Is there any reason why 2 2 gig sticks of RAM wouldn't work in the iMac? (or MacBooks for that matter)
 
You're the resident RAM expert :D Is there any reason why 2 2 gig sticks of RAM wouldn't work in the iMac? (or MacBooks for that matter)
I don't think the motherboard/chipset can address 4GBs. Sure, you could throw 2x2GB of RAM in there, but your computer wouldn't see it. I don't have any links, but I'm fairly certain I've read this being tried before...

SR should fix that though!
 
The Core2Duo models of the MacBook Pro and the iMac will physically accept 2 x 2 Gb, however the chipset will only permit 3 Gb of that to be addressed by the OS. So there is no point to installing 2 x 2 Gb instead of 1 x 2 Gb + 1 x 1 Gb

A similar issue exists with PC Core2Duo notebooks - you can't use more than about 3.2 or 3.3 Gb of the 4 Gb.


The Core2Duo MacBook is more of a puzzler; Apple have steadfastly held to a 2 Gb total (2x1G) on this machine notwithstanding it is the Core2Duo chipset. But it is not the identical motherboard/chipset as the MacBook Pro (integrated video being the most obvious difference). We'll test out the theory first chance we get,
 
I'm almost certain 3GB RAM will work in the C2D Macbook. The reason why Apple isn't recommending this (or making it possible to add via a BTO) is because the GMA950 on the Macbook provides best performance with dual-channel RAM. With 3GB, only 2GB will run in dual channel. Thus, Apple doesn't "officially" recommend the practice (on the Macbooks.) The OWC info seems to brush this off, claiming the overall system performance (on a Macbook) is better w/3GB RAM. But at the same time, they don't seem to really address the issue of what kind of hit the onboard graphics will take... Meanwhile, since the Macbook Pros don't use the GMA950, Apple is providing a BTO option for 3GB. Make sense?

Why units are limited to 3GB RAM

The actual thing is that, in a 4GB configuration, when all the amount of RAM is being addressed, there is some overlapping. This does not happen in a 3GB configuration. The problem occurs only when the system memory attempts to occupy space that is already assigned to functions between 3GB and 4GB.

intel-system-memory-map.png


Dude, where's my 4 gigabytes of RAM?

... it's an x86 hardware problem. The memory hole is quite literally invisible to the CPU, no matter what 32-bit operating system you choose.

...The proper solution to this whole conundrum is to use a 64-bit operating system. However, even with a 64-bit OS, you'll still be at the mercy of your motherboard's chipset and BIOS.
 
has anyone here actually installed 3gb ram in a macbook?
I'm sure that one or two people have posted their personal findings after doing this on other threads - there's been various discussions on a lot of other sites (e.g. MacFixit).

Don't know if you've seen it, but OWC have a page which benchmarks MacBooks with various amounts of RAM - http://eshop.macsales.com/shop/Memor...Apple_MacBook/

In terms of user experiences posted, I think the main feedback is if you're running loads of apps at the same time, there is a benefit albeit an expensive one.
 
Why the hell would they limit it to 3 though? If I remember correctly from my computing internals class (which I probably don't since I was either sleeping or playing games on my phone), a 64 bit proc is capable of addressing something like 16 exabytes of RAM. Obviously, no one will ever come close to that number, but why 3 gigs? They could've done 4 at least....
 
Looks like a very nice and legit company.

Love your sig, it is overkill. Serious overkill.:D

Thanks, I made it myself. It's also kinda cool that my macbook (2.16 GHz with gb ram and 120 gb hard drive) is probably quicker than some (mostly rev A) MBP's (minus the graphics card obvoiusly)
 
We'll test out the theory first chance we get,

Hadn't you posted something before about not being able to boot a Mac with a 2GB module in it? Was it a Core (One) Duo Macbook, and not a C2D?

To the OP: How much memory do you have now? The best way to tell if you'd benefit from 3 GB would certainly seem to be whether or not you get page-outs at 2 GB.
 
Interesting. If you take a close look at their numbers though, it appears that the gain in going from 2GB to 3GB of ram is very small compared to the cost. Given that a 2GB kit can be found for $75-90, the extra ~$100 doesn't seem to be particularly well spent.

http://eshop.macsales.com/Reviews/MacBook/Testing/Memory_Benchmarks

That depends on what you are doing. If 2 GB is enough for what you are doing, you are fine and 3 GB will not help you one bit. If 2 GB is not enough, it will help a lot. If you look at these benchmarks, almost all have very little variation with the amount of RAM, except for a few that show that 512 MB is not enough and where adding a bit of memory made the benchmark twice as fast.

You might be using Photoshop and juggle around 100 MB pictures all day, and 2 GB is enough for you, but if you juggled around 150 MB pictures all day, your machine might come to a crawling halt until you upgrade to 3 GB (just an example).
 
Why the hell would they limit it to 3 though? If I remember correctly from my computing internals class (which I probably don't since I was either sleeping or playing games on my phone), a 64 bit proc is capable of addressing something like 16 exabytes of RAM. Obviously, no one will ever come close to that number, but why 3 gigs? They could've done 4 at least....

They have a limitation of 4 GB. But the limitation is for everything that needs a memory address, and that is RAM, video hardware, Firewire hardware, and so on, and so on. If you see a "256 MB video card", that 256 MB needs an address and it comes out of the 4 GB. So there is probably something like 3.5 GB left for memory, and Apple avoids awkward questions ("why do I have only 3.47 GB when I put 4 GB into my MBP") by not offering more than 3 GB.

And 64 bit processors can't actually address 16 exabytes of RAM. The G4 could address 64 GB (even though it is only 32 bits...), the G5 can address 4 TB, don't know what the limit is on CoreDuo and Core2Duo but probably not much more; could even be less.
 
The Core2Duo models of the MacBook Pro and the iMac will physically accept 2 x 2 Gb, however the chipset will only permit 3 Gb of that to be addressed by the OS. So there is no point to installing 2 x 2 Gb instead of 1 x 2 Gb + 1 x 1 Gb

A similar issue exists with PC Core2Duo notebooks - you can't use more than about 3.2 or 3.3 Gb of the 4 Gb.


The Core2Duo MacBook is more of a puzzler; Apple have steadfastly held to a 2 Gb total (2x1G) on this machine notwithstanding it is the Core2Duo chipset. But it is not the identical motherboard/chipset as the MacBook Pro (integrated video being the most obvious difference). We'll test out the theory first chance we get,

Two questions: Do you know what would happen if you insert 4GB into a MBP? Does it come up with 3GB, or a bit more, or does it not recognise the second chip at all? And the second question for the expert: We read here occasionally of people who add their own RAM, don't push it in hard enough, it doesn't work, and after pushing a bit harder it works. Do you know if there is much risk of permanent damage to the MacBook and/or the memory if you don't insert it properly, or does it just not work until you do the job right?
 
They have a limitation of 4 GB. But the limitation is for everything that needs a memory address, and that is RAM, video hardware, Firewire hardware, and so on, and so on. If you see a "256 MB video card", that 256 MB needs an address and it comes out of the 4 GB. So there is probably something like 3.5 GB left for memory, and Apple avoids awkward questions ("why do I have only 3.47 GB when I put 4 GB into my MBP") by not offering more than 3 GB.

But the iMac has a dedicated video card and dedicated memory for that.
 
Two questions: Do you know what would happen if you insert 4GB into a MBP? Does it come up with 3GB, or a bit more, or does it not recognise the second chip at all? And the second question for the expert: We read here occasionally of people who add their own RAM, don't push it in hard enough, it doesn't work, and after pushing a bit harder it works. Do you know if there is much risk of permanent damage to the MacBook and/or the memory if you don't insert it properly, or does it just not work until you do the job right?

Apple says (and I believe) that only 3.0 Gb will be recognized.

On any of the machines, the RAM has to be properly inserted into the socket, In the iMac and MacBook machines the RAM is pushed straight in to a recessed socket. When you push it in, there is a 'thunk', it is NOT seated yet, you have to push harder and it moves in another 1/8" (2 mm) into the socket.
If you don't get it all the way in, typically the machine will start to boot but hang on a black screen. There is potential to damage your data there, just like any crash. I have not seen a machine damaged physically from this, yet.

There have been a few reports of sockets and power connections on the motherboard becoming damaged from excess force installing, from pushing it in with the RAM reversed (that is, the slot in the module not oriented with the key of the socket) or just outright socket failure.

Hadn't you posted something before about not being able to boot a Mac with a 2GB module in it? Was it a Core (One) Duo Macbook, and not a C2D?
That was a Core(one)Duo
 
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