View Full Version : DDR400 (PC3200) RAM in the 1.6 GHz G5?

Sep 29, 2003, 05:16 PM
Hi there!

Just wondering if DDR400 (PC3200) RAM will work in the G5 1.6 GHz machine. I believe the general rule is that your system bus has to be twice the speed of your RAM when using DDR, so technically, at 800 MHz, the G5 1.6 GHz should be able to handle 400 MHz RAM, no?

Also, if I wanted a 1.8 GHz G5, would there be any issues if I left the 2x256 MB sticks of RAM in the machine, and added my own RAM in the remaining slots - either 1 512 MB stick, or 2x512 MB sticks? Or should I remove the 2x256 MB sticks?

Lastly, is Mac RAM "special"? I have a friend who can get PC components at cost, and was wondering if I ordered some of his "PC" RAM, if that is essentially the same, and would work in a Mac as well....

Any advice is appreciated!


cc bcc
Sep 29, 2003, 05:30 PM
You can use DDR3200 RAM, but it will run at 366 MHz (DDR2700 speed) not 400, the frequency is controlled by the memory controller, not by the dimms themselves. And the G5 1.6 runs it ram at 366 MHz effectively. You will be underclocking the ram and waste money, don't do it!


You add the dimms in pairs. 2x256 and 2x512 will work fine.

Not all pc dimms will work fine, there is a thread about this already.

Sun Baked
Sep 29, 2003, 05:51 PM
If you need a bit more info, which would be a good idea before ordering there is the Developer Note on RAM (http://developer.apple.com/documentation/Hardware/Developer_Notes/Macintosh_CPUs-G5/PowerMacG5/4Expansion/chapter_5_section_2.html#//apple_ref/doc/uid/TP30000805/TPXREF102)