There are six machines in the A1278 Model. Some will take a maximum of 6 GB of RAM and some will take 8. So Bac is the only one here that gave a correct answer. Machine identification is critical and answers given without that information are just guesses.

according to various sources, including this one, and also Mactracker, you CAN install up to 6GB of RAM in the MacBook Unibody A1278 (aka MacBook Late 2008)

the same source mentioned above also mentions that real-world testing shows an almost negligible performance difference running match RAM modules vs running 2GB + 4GB

i would recommend to go with 4 GB as recommended from Apple, I installed 8 GB and didn't noticed significant difference.

Whether or not more RAM will benefit you depends completely on your usage. I have my Mac mini maxed out at 8 GB, and I wish I could stuff more in there--I get a lot of pageouts, depending on what applications I have open. In general, it behooves one to install as much RAM as one can afford. Especially if one uses Adobe or other memory-hungry apps.

Hi guys, this is what i read in everymac.com regarding the max RAM you can put on A1278. I hope it works. I will give it a try with 8GB:

"Apple officially supports a maximum of 4 GB of RAM. Originally, this model was only unofficially capable of stably supporting 6 GB of RAM, but as confirmed by site sponsor OWC, it is capable of supporting 8 GB of RAM if updated to Boot ROM Version MB51.007D.B03 and running MacOS X 10.6 "Snow Leopard" or higher"

Martin

Apple says 4 GB but some people have installed 6 GB. A 2GB and a 4GB.

Ralph

I'm running 6 GB with no issues whatsoever.

Had installed 8 GB for about a day, didn't have any problems, unfortunately had to give one module back to it's owner :(

My mac have seen 8 GB (7.75 GB as 256 MB goes to graphic card...)

i did the same, i replaced my 2 GB with 8 GB.

in Mac, i didn't notice much difference, but in Windows 7 it is so fast.

I just installed 8 GB of RAM from Crucial in my A1278 without any trouble. Its registering as 8 in "About this Mac" and in the Activity Monitor. We're sailing smoothly! :)

@mattapoisett, e.g. try to run some virtual machines simultaneously with 4gb. then you will see the big difference.

Alright, if i installed 8GB, will the mac recognize it as 8GB?

and what's the recommended ram type for 6GB or 8GB?

Thanks.

someone said that 8gb would cause problems, but i highly doubt that. regardless, if you boot into windows 7 it'll recognize 8gb. i'm sure there may be some developer options to unlock the 6gb limiter.

I bough 8GB as I read on the Crucial site that it accepts up to 8.... So im a bit worried that it says 'maximum 6gb' here...... System profiler recognises 8GB but the system has become sliiiiightly less stable.......

i'm about to replace 4g ram with 8g ram on mbp 13" A1278. will i notice a significant difference?

So im still confused will the completed 8gb upgrade wont get me any trouble? i had this model A1278 macbook 2.0ghz core 2 duo.

Best regards.!

i would recommend to go with 4 GB as recommended from Apple, I installed 8 GB and didn't noticed significant difference

the latest version of mactracker states 8GB actual, 4GB by Apple

I purchase and install 4GB Elpida and it goes plenty Good.

Best regards and wishes from Canary Islands!

i just tried 8gb in my mac book 13 A1278 with mac os x lion and it's running for some hours now without any problems. :)

My Wife has a MBP Unibody 13" 2.26 GHz (Mid 2009) and it's slow when she uses Aperture if she then opens Parallels the machine becomes unusable. We have 4 GB in it now [2x2gb] and the spec sheet says thats all it will take but I have seen hints of a possibility that the machine may accept up to 8 Can anyone confirm ? and if it can't, are their settings in Aperture or Parallels to make them less of memory hogs?

mattapoisett, Mactracker says that MBP can take 8gb. For Aperture and Parallels, I would fer sure max it out.

'And now im really sad because i purchased my 4GB and it works well but if i can put more ram i will do it because it wont work so fast with vmware 4.

Thanks a lot for your support. ''

The 8 GB came in the mail today and installed easily and there seems to be no problems with it.

Here's part of a write up I found on memory, hope it helps.

If you look back when your system (desktop or laptop) was introduced and looked at what memory was available you would have noted the memory modules were quite large physically from what we have today.

- Cost was high for any of the larger memory SIMMs

- The I/O speeds were not as fast as what we have today

- Power and heat was a big problem

While desktops had plenty of power, laptops didn't so it was not uncommon for laptops to have less memory or was limited due to the heat buildup and running time.

Today things are much better even for older systems!

- With super high density chips now being used in SIMMs the power and heat issues are a thing of the past.

- Memory limits placed by the laptop manufactures to meet their usage claims (how long you use your laptop) is no longer the the killer.

- Memory cost have also dropped (not as fast as hard drives though) so more people are willing to buy more.

Guidance:

- With newer high performance systems interleaved memory is more important (Vs straight I/O).

- If you have an older technology SIMM (larger chipped) in your system its best to throw it away if you're in the process of adding memory.

- Use a matched set (bought together) when ever possible. Mixing older tech SIMMS with newer tech SIMMs often make an unstable system.

- Always check your firmware (BIOS/PRAM/vPRAM) is at the latest for your system

I installed 8GB (2x4GB) in my 2ghz core duo A1278 and changed the 160GB Hard drive to a momentus hybrid 500Gb and the laptop was screaming fast in comparision to the pre-updates system.

It identifies ALL 8GBof memory and it runs statistical analysis regressions faster than my Quad core i-7 920 running at 2.8GHZby a factor of about 6-10 times.

I ran all the database and merging processes on the i-7 then ported the data out to the macbook to run the regressions. I couldn't believe the performance difference between the two systems. The i-7 has 12GB ddr3 1600mhz memory and 7200 rpm drives.

So yes the upgrades to the mac book were worth the investment.

Only thing faster is current generation processors (>2.5Ghz i-5/i-7) with full SSD drives.