My Macbook came with 2x512kb of RAM. So if I buy a 2GB memory stick do I keep the 512kb in the other slot or take it out?
If it's the original Core Duo MacBook, the chipset does not support 2 GB modules at all. If you put it in, then at best, your MacBook will see 1 GB of that, at worst, it won't work at all. In order to get 2 GB, you need to use two 1 GB modules. If you have an original Core Duo MacBook, do not use a 2 GB module, it would be a horrible waste of money.
The first Core 2 Duo models support 3 GB total, and so properly support one 2 GB module, and one 1 GB module. If you have one of those, then yes, leave your 512 MB module in.
The newest "Santa Rosa" Core 2 Duo models support 4 GB total, for two 2 GB modules. If you have one of those, then yes, leave your 512 MB module in.
Hmm I am not sure which model I have. The part no. on the box says MA701LL/A if that helps. It is a 2GHz black one. The box also says it supports up to 2GB of RAM.
You can keep the 512MB stick in the other slot, but since you can only max out 2GB, it would be wiser to get two 1GB sticks instead. Apparently RAM works better when you have identical sticks in each slot.
Just like apple previously said the MP could only max out at 16gb of ram, apple is basing it on the max ram they can fit into a stick of ram at the release time.
Not entirely true. The core duo macbooks can only address 2GB of ram and the core 2 duo's up to the rosseta (you mean Santa Rosa here. Rosetta is the name of the emulation software that allows Intel Macs to use PPC apps) could only address a max of 3.3GB.
Its the limitation of the motherboard chip set they are using in this case.
Otherwise if you want dual channel (just about 2% better performance), then get 2 chips of the same 2gb ram. Only 3gb will be available but then it will have dual channel.