RAM issues on PowerMac G4


I've had my G4 dual 1.42 for a couple of years now. I had 1.5GB of RAM installed when I ordered it. I recently decided to add another 512MB chip to max it out. However, after installing the chip, a bunch of programs started shutting down intermitantly and then it wouldn't boot up fully after I restarted. I couldn't even reset the PRAM. I pulled the new chip and was able to get the system back up and running. But now, even with the chip out, I'm getting some sporadic problems with programs shutting down or behaving correctly.
I read on Apple's site that some programs wouldn't recognize more than 1.5 gigs of RAM and would have problems running. Here's a link to the article:
Has anyone else had a problem like this? I would like to have the extra RAM, but not at the cost of these issues. And why would I still be having problems after uninstalling the new RAM?

Power Mac G4, Dual 1.42 GHz, 1.5 GB RAM, OS 10.4
I'm having issues after installing an additional 512mb RAM as well. My machine's not as "robust" as yours. G4, 350mz processor, 64mb RAM original(128 added) and then 512mb added. I couldnt install tiger on my box with the 512mb RAM in there so I had to take it out to install it. But i NEED the extra RAM to install other programs and run them. So when I stick the RAM back in, I get problems. I'm guessing that's the RAM, but I dont know if that means that it's bad, or that I just cant use that RAM. It's supposed to be compatible according to the people who sold it to me, so I'm guessing it's bad. BUT it shows up as there(704mb RAM) in the settings. So dont know if that means it's bad or not.

I'm stumped.
I'm wondering if it is an issue with Apple RAM not playing well with third party RAM. I got my chip from memorytogo.com and found I couldn't just return the chip for a refund. They sent me a new chip to replace the first. I'm afraid to even try the new chip so I'm just going to sell it and take a loss.
Like your system, mine would recognize the extra RAM but was having difficulties even after I pulled the chip.
Like you, I'm perplexed.
Mac OS X is very picky about RAM timings. Some PC memory are not top-of-the-line and even though it might work on a PC that isn't that picky about memory timings, it will cause a Mac to crash. I always stick with brand names when it comes to memory whether I get it for a Mac or a PC. Corsair, Kingston, Crucial, GeiL, etc. are all good brand names and make quality RAM at decent prices. Also, be sure you get it from a well-known vendor like NewEgg, ZipZoomFly, etc. Otherwise you will end up paying more in the end (and not just monetarily).
You also DON'T want to mix and match memory. Make sure you are consistent with the memory you install. Same brands, same timings, etc.