Hello... Just got a 450 DP G4 Mac and I was wondering if I could put in some 133 chip RAM in my model (Apple says only 100). But a friend of mine did it... And it seems to be working fine.

Second, can you combine the diferent models? 100 + 133 on the same machine or should I go with only one standart?

This is because 133 is cheaper...
Thank's

Yes you can but I believe that sometimes the ram fails to be recognized by
the OS. I have some PC133 in my systerm (same as yours sounds like, GB DP
G4 450) and it works fine.

If it does work, you will not get the advantages the PC133 gives as it will
run as if it were PC100.

Where did you find cheaper PC133 than PC100?

that is correct you may be able to get the slower RAM to work but it will run at the speed of the slower RAM.

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You may find that the machine won't recognize the RAM. If this happens, there is a trick that might work. Hold down the option and open apple keys while opening the Memory Control Panel. This will give you an extra option to turn off memory tests at startup. This might let the RAM sneak through and work. If the RAM doesn't meet the machines specs, sometimes the tests will shut down that particular slot and ignore it. This can avoid that.

The 133 chip should work fine. It will simply operate at a clock speed of 100 rather than 133.

If your Mac fails to recognize the chip, it's not because of the different clock speed, it's because the recent Apple firmware upgrade doesn't recognize chips that only operate at a CAS latency of 2-2-2, as opposed to both 2-2-2 and 3-2-2. This can happen with PC-100 as well as PC-133 chips. If it happens, just exchange the chip for one with the more flexible latency spec - most chip vendors are willing to do this. If you can't exchange the chip, do a search for Glenn Anderson's free DIMMFirstAid program, which will re-configure the chip for you. A link to that software was provided on the MacNN news page a few days ago.

Just to add to what Zigzag said, turning off the memory tests was the solution Apple suggested to someone I know to fix the firmware update issue. That might be easier than returning RAM or reconfiguring it. Of course, if the chip starts to go bad, your machine might start to act a little funny because the test didn't run and find the problem.

Paul is correct that some people have circumvented the problem by bypassing the memory test at start-up. From what I understand, the chip would probably still work fine. However, the reason for Apple's firmware upgrade was to increase stability by making sure that memory works at CAS latency ratings of both 2 and 3. If your chip only operates at 2, you might not get optimal stability. But bear in mind that this is probably all moot - odds are very high that any chip you buy will conform and you won't have to worry about any of this.

Focusing on your original question, the fact that the chip is PC-133 is of no concern whatsoever. In fact, some authorities recommend using chips with an extra margin of clock speed, believing that it also enhances stability. So go ahead and buy it. I only recommend that you buy from an established source that will accept returns or exchanges in the event of problems, but that would be true whether it was PC-100 or PC-133.

Wow! Thank's all for your serious answers!

And, just to be sure, I can mix-and-match as much as I want different speed RAM on my G4 (Say 3 100 and 1 at 133)?

Thanks all again!

to answer "Brown Monk" I live in Canada (near Ottawa) and at Futur Shops (kinda like a CompUSA in the states) they were (I missed it) selling 256MB ram 133 at 99$Can which is 65$US...

I got my ram(128MB 100) at the same time as my machine last week for 80$Can (50$US)... So for a little more I could have double my ram in both mahcines (I bought 4x 128MB 100, this was cheaper than buying 2x256MB at that time. I know it uses more of my slots)

Yeah - you can mix and match as long as each stick is compatible with your machine. Sounds like you'll be fine.

thank's zigzag...

Now if I can only get the next sale!

The DP 450, like my DP 500, will only use PC133 RAM at the PC100 speed, mixing and matching makes no difference for us. It does work just fine. Get the 133 though, it's cheaper.