This can get a bit confusing ;-}
So lets start off thinking back in 2010 where things stood. Apple sold the system in two configs one with 2 GB and the other with 4 GB. So at that time point Apple did all of there testing with these two setups hence what Apple supports. Within a few years memory manufactures came out with 4 GB memory modules. But Apple had already ended the production of this system (Feb 2012) so Apple never attempted to test the system with more memory.
Now its some where in 2012 the memory folks want to sell more memory and people are bugging them to test the system with the newer 4 GB modules. So at that time point the memory folks tested things out and their test showed the system could support the bigger modules so you could go up to 8 GB!
Sadly, the still newer 8 GB modules would not work, this was due to two different issues the first was the OS its self as it was still 32bit (Lion being the first full 64bit version) and the other was the systems firmware. As it turns out the hardware was wired to support the larger modules but the way the memory addressing worked prevented the use of the 8 GB modules.
Then things get a bit strange here... People still wanted more memory! And pushed Apple to fix the firmware so the systems could support 16 GB. Apple relented and came out with a firmware update and stated they would support 16 GB. Apple never offered a firm document stating this and the way it was stated left them a bit of wiggle room (in case it didn't work so they didn't get sued).
So now were back to today! And here is the answer:
- Your system can support 16 GB of RAM using the latest firmware and using the newer versions of OS-X (Lion or newer).
Now before you jump here adding more RAM you may want to cool your jets a bit here!
First Core2 Duo systems run better with the older versions of OS-X (Mountain Lion being the best). Depending on what you are running for apps you might want to think about downgrading.
Even with Yosemite you most likely won't find adding more RAM (more than 8 GB) as being as beneficial than upgrading your HD (if that is truly whats needed here). So if you already have 8 GB in your system I suspect you'll want to look at your HD a bit more.
More often than not I find people don't have enough free space on their drives and with traditional HD's failed to maintain them. So here is what I do:
- Boot up under an external drive and run Disk Utility to check & repair the HD's permissions & disk.
- Clean out the old cache & log files. I like this App: Disk Doctor
- Clean out as much stuff as I could to leave 1/4 to 1/3 of the drive free
- You really need a good defrag program to clean things up. I like this one: Drive Genius
After doing all of this you should see the zip you had when you got your system!
OK, you still want or need to upgrade your drive. Then I would recommend you go with this drive: Seagate Laptop SSHD. We have quite a few in the field and have found them very reliable and offer a good half step to the speed benefits of a SSD. You do need to be careful here as your system only has a SATA II (3.0 Gb/s) drive interface so what ever drive you go with needs to run at this SATA I/O speed.
You also talk about going with a dual drive system. If you do you want to keep the HD in its current location and put the SSD into the optical bay carrier.
But be careful here loading up these older systems may overtax them! Between the heat build up and the power requirements. Think how you are planning on using your tricked out system: Plugged in or on battery? Are you doing heavy graphics? These will effect how far you can push your system.
35 
329 
971 