Max Ram and type in Powerbook G4 1.67mhz

That's right: none.

Depending on which model 1.67GHz PowerBook you have, the low-res version A1105, or the high-res version A1106, the memory will differ.

The maximum RAM is the same though. 2GB.

If you have the low-res, you'll want the PC2700 RAM, if the high-res, you'll want the PC4200 RAM (but as I've noted in other places, PC5300 RAM will work just great for the high-res version).

Go here for just one source of possible RAM for your machine. (You can try other places too).

http://eshop.macsales.com/shop/memory/iBooks-PowerBooks/G4-Aluminum/

NOTE: as also noted by me and others on these forums, PowerBooks are very picky about the RAM you put in, so it should be Samsung, Hynix, Micron, or Crucial brand memory, all OEM suppliers for Apple. I've personally used PNY memory in my 12-inch PowerBook (I know, not the same as your 15-inch) and it works perfectly. Some will say Kingston, but make sure the part no. starts with "KTA- ____" and is not their Value RAM series.

Yes, screen resolution.

PowerBook 5,6 is the low-res model with 1280x854 resolution, thus you will need the PC2700 RAM

PowerBook 5,8 is the high-res model with 1440x960 resolution and had a Double-Layer SuperDrive.

Yes, as I mentioned, PC2700 is for your machine.

But, it's up to you whether you choose to upgrade to 1.5GB total by purchasing a 512MB module to add to your existing 1GB, or, as I recommended, since you're already at it and spending the money, go for the maximum upgrade and get a 1GB module since the most your machine can handle total is 2GB.

And if you decide to upgrade again later in the future--assuming you bought the 512MB module--you'll end up spending more in the long run since you pay, say $40 now for a 512MB and later, $60 for the 1GB which means $100 spent, as opposed to spending "more" once.

(Those prices aren't based on any website. Just threw those numbers out there).