Hi all.

I have a MacBook (2,1; late 2006; MA701LL/A, Black).

In June, I upgraded the RAM to what Apple says is the maximum, 2.0 GB. The actual maximum RAM the OS reads under my processor -- Intel Merom T7200 ("Core 2 Duo") -- is 3.0 GB.

My question: how much will performance be hurt by having two sticks of memory that are not the same exact type at the same time? I know since these are DDR2, they have a performance boost when installed in combination with others of the same type/size/speed... but I don't know how much it'll be affected if I have a 2.0 GB stick and a 1.0 GB stick installed at the same time.

What will be affected? How will it be affected? Is it really worth it?

All input appreciated. Thanks. :D

I guess people here aren't knowledgeable enough. Thanks anyway.

More chances than not, it'll be fine. If the RAM is clocked differently, I believe the higher stick will downclock to match the lowest denominator.

Of course, I'd pick the same clock speed, 667 MHz, which is the one it accepts at a maximum.

Thanks for the reply.

Its a very smart idea!

I have 3GB of RAM in my MacBook. I upgraded after viewing these benchmarks (see link below). For the vast majority of tasks the MacBook is faster with the 3GB. The only reason Apple recommend you install the memory in matching pairs is because of the Intel integrated graphics. As this uses system memory rather than fast dedicated video memory fast performance from RAM is considered a priority. Having two matching pairs allows for 128bit memory addressing.

In theory unmatched pairs could potentially could result in slightly poorer gaming performance, but for me this is more than offset by the increase in performance everywhere else. Besides, the MacBook isn't exactly great in the gaming department anyway!

This why Machines such as the MacBook Pro and the iMac can be specified on the apple site with unmatched pairs, they have dedicated video cards.

see the benchmarks here:
http://eshop.macsales.com/Reviews/MacBook/Testing/Memory_Benchmarks
and here:
http://www.macsales.com/newsletter/5-31-2007OWCTipsnDeals.html

The best possible spec for a MacBook would be two 2GB sticks. Although the motherboard chipset can only read 3.3GB of RAM, you would get 3.3GB and 128bit memory addressing as the memory sticks are the same size. On systems configured like this OS X's system profiler only says 3GB of RAM availible, despite 4GB installed :(.

Interesting, very interesting. I knew there was something in there that would get "messed up"... but luckily it's something that I don't really care about. The highest graphics I'd want to get from the video card here would be World of Warcraft and I don't even play that anymore.

I'm now down to simpler games. Take Galcon (http://www.imitationpickles.org/galcon/index.html) for example:

http://www.imitationpickles.org/galcon/content/19.jpg (warning: addictive!)

I'll see what I'll do and update as soon as I do something. Thanks for the interesting info, I didn't know that 3.3 GB reading limit. I thought it was 3...

I wouldn't worry about the drop in gaming performance, in the benchmarks i've seen you generally lose 1 to 2 FPS in Mac OS X based games, not particularly noticeable. You should find WoW plays much as it did before.

The only thing I am unsure of is how it affects running games in windows under boot camp, but I haven't been able to find any benchmarks, and I am too lazy to try doing them myself!

I see. If I find anything, I'll post it here.