RAM for a G4 (Digital Audio) 467 MHz?

Question

Hi,
The mac I use at work is (I think!) a G4 (Digital Audio) 467MHz model running OSX 10.3.9 Panther. My employer has said he will consider ordering more RAM for the computer and has asked me to do the legwork. Ideally I want to max out the RAM on this computer because it's unlikely my employer will be replacing it any time soon.
From reading this forum, I gather that Macs can be picky about RAM - I'd like your recommendations about what/how much to buy. Currently two slots have RAM of different sizes - am I correct that the computer will work more efficiently if all the slots have the same size RAM?
Here are the specs for the computer:
Hardware:
Hardware Overview:
Machine Model: Power Mac G4
CPU Type: PowerPC G4 (2.9)
Number Of CPUs: 1
CPU Speed: 467 MHz
L2 Cache (per CPU): 1 MB
Memory: 640 MB
Bus Speed: 133 MHz
Boot ROM Version: 4.1.8f5
Serial Number: XB1240YYKXS
Sales Order Number: 0100426226XB1240YY1234123412341234
Software:
System Software Overview:
System Version: Mac OS X 10.3.9 (7W98)
Kernel Version: Darwin 7.9.0
Boot Volume: Macintosh HD
Memory:
DIMM0/J21:
Size: Empty
Type: Empty
Speed: Empty
DIMM1/J22:
Size: 512 MB
Type: SDRAM
Speed: PC133-333
DIMM2/J23:
Size: 128 MB
Type: SDRAM
Speed: PC133-333
DIMM3/J24:
Size: Empty
Type: Empty
Thanks in advance for your recommendations!
frano

Answer 1

Your G4 DA uses 168-pin PC-133 (unregistered, non-ECC, non-parity) SDRAM. A 16-chip (8 chips on each side), 512 MB DIMM is the largest that's supported in each memory slot. As long as the SDRAM meets the criteria, it doesn't need to be purchased from a Mac memory dealer, although you may have fewer compatibility problems (since some memory merchants aren't really familiar with Mac memory requirements). Unlike some PCs, Mac OS X doesn't run well with inexpensive/marginal quality memory, so your choice shouldn't be based on price alone. You can check out this dealer's prices, and compare prices at Ramseeker.com.
As far as mixing memory having different density chips, you may find a performance boost by using similar-density memory. A 512 MB DIMM with 16 chips and a 256 MB DIMM with 8 chips both have 256-Megabit chips. A 16-chip 256 MB DIMM and an 8-chip 128 MB DIMM have 128-Megabit chips. A 16-chip 128 MB DIMM has 64 Megabit chips. If your 128 MB DIMM is low-density memory, having more than 8 chips (either on one side, or 4 on each side), I'd remove it and replace it with something larger.