Computer memory upgrade confusion

Question

I am interested in adding memory. When I read the information on the Apple support page for upgrading memory it tells me that my G5, 1.8 mhz, dual processor machine should use memory that is "333mhz, pc2700". However, when I look at information in "about this mac" I find the two 256 meg memory sticks that are installed are listed as "256 mb DDR SDRAM pc 3200u-30330". Apple info says that the pc 3200 memory is only used in machines that have eight expansion slots and can hold 8 gigabytes of memory. My machine is only upgradable to four gigabytes. I really do not know what pc 2700 or pc3200 means. The current memory was ordered as an upgrade and installed at the factory.
My plan is to add two 512 meg memory sticks in the slots currently used by the 256 meg sticks and move the current memory sticks to the open slots.
I am confused about what type of memory I need to purchase.
Any help and clarification would be greatly appreciated.
PowerMac G5, 1.8mhz, dual processors   Mac OS X (10.4.3)   512 megs RAM

Answer 1

You don't need to move the existing RAM, they can stay happily where they are. Just add the two new RAM modules to the two remaining memory sockets.
As for the type of RAM, your dual 1.8 G5 needs RAM of the following type DDR SDRAM, pc2700. However the pc2700 is a reference to a speed rating of the RAM module. pc 3200 is the same type of RAM but can work with a faster memory bus. As a results, pc 3200 will work fine in your G5, though there will be no increase in performance, just because the memory can run faster, your G5 is still running at its rated bus speed.
Sometimes, it can be cheaper to put the faster rated RAM in. This is because more of the faster rated RAM is produced, driving down its cost, while less of the slower RAM is made, keeping its price steady or even goes up.
DDR SDRAM pc2700 or pc3200 should work fine.
Tom N.