Installing 4 Gigs of 800Mhz DDR2 RAM into a Macbook that won’t take it…

Ok I have this black Macbook that I got last August, my first ever Mac and I love it,  Macs  just make life so easy, especially since most of my servers are Linux based. Whenever I need to use Windows I just use a VM, VirtualBox namely.

Anyway, I found that overtime the 2 gigs of RAM that I had in this mac would fill up from all the applications I had open. The logical choice was to get more RAM. I bought 4 gigs in total, in a 2 x 2gig config. The RAM was from Crosair because that’s my preferred brand.

I knew that the RAM speed on my Macbook was 667MHz and I intentionally bought that RAM at 800MHz so that they RAM could be used in future machines should I ever upgrade and I wouldn’t have to pay the extortionate amount manufactures have to install more RAM. So when I took out the 2 gigs that was in my Macbook and installed the 4 gigs, which wasn’t that much trouble either and turned it on, nothing would work. I mean it didn’t even get to the loading OS X screen.

So I thought that the RAM might be DOA which can happen, so I installed the RAM into my XPS Vista Laptop and it worked fine and underclocked the ram back to 667MHz like I thought that Mac would.

I went online and had a look at any solutions or causes for this. The ram was all fine and so was my Mac so wasn’t too sure what it might. Macforums gave me the answer like it usually does. Great forum for Mac users. On it they mention that because Macs don’t use the 40 year old bios technology (instead they use EFI) there will be a problem if the RAM is not configured correctly, ie: if the EFI cannot read the RAM to determine what speed to run it at.

Well that seemed like a pretty logical explanation to me. So the solution was on the next page of the forum where a guy at actually flashed the RAM again and told it to run at the lower speed so that they Mac could use it. You only need to do this to one stick of the RAM the EFI will tell the other SO-DIMM to run that the lower speed. (Doing this probable does void your warranty, I have not checked though).

So the program is called SPDtool and runs under Windows. I have XP install as a dual boot using Bootcamp so it wasn’t too much work to get it up and running. When you load the tool it gives you a pretty simple display where you can read all the configurations flashed to the Ram modules, it also allows you to changes them from a drop down list and to flash them to the ram again, which is what I did. Here are the steps.

1. To get the Mac to boot with on of the 2 gig modules, use a 2 gig module and 1 of the previous modules of RAM at the same time, it will boot then. In my case it gave me 3 gigs of RAM in total.
2. Boot into Windows using BootCamp. I used XP Pro SP3, it should not matter though as long as it is XP or Vista
3. Load the simple SPDtool from the exe.
4. Select the Module to read. (The one thing about this tool, it didn’t make it easy to figure out which module I was reading, ie: It did not show the amount of ram in each module which would would easily allow you to figure out which module you will read and then edit. I chose based on the current clock speed of the RAM, I know my old RAM ran at 667MHz and the new one ran at 800MHz).
5. Select the SDP to be 666MHz (I also thought it was a bit odd that it did not say 667 but it worked anyway. Could be just a mis type for the text of the drop down list)
6. In the Edit menu, recalculate the checksum for the RAM. This is an absolutely essential step, if you do not do this, the ram will not be usable by any computer as the computer will not load if the checksum is incorrect.
7. Then write the changes to the the same RAM module. (When it was writing the changes to the ram, the program froze on me so I thought it had crashed and destroyed my RAM but it recovered and finished the job.)
8. Next I changes the old RAM module (1 gig stick) for the the one that was not flashed by me.
9. With the 2 x2 gigs of RAM in my Macbook, one stick flashed to 667Mhz and the other to it factory default of 800MHz, I reboot my Mac and all was well. The Macbook recognised that I now had 4 gigs of RAM running at 667Mhz.

Perfect…