Question about RAM

MacAztec

macrumors 68040
Original poster
Oct 28, 2001
3,023
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San Luis Obispo, CA
I am going to buy a 512MB RAM chip for my G4 500 AGP. I think it uses PC 100 RAM, but wont PC 133 RAM work in it? I am buying it from best buy for 100 dollars...it is the cheapest place to get RAM.
 

MacAztec

macrumors 68040
Original poster
Oct 28, 2001
3,023
1
San Luis Obispo, CA
HELP!

I bought my 512MB PC 133 RAM. I put it into my G4 500 AGP, and now the Monitor wont start, nor the computer!

I take the RAM out, and the computer works? Do macs not work with this RAM?
 

germanknee

macrumors member
Jan 24, 2002
79
0
best buy does not sell ram for the macintosh. that's your problem. Also, buy pc100 because it's cheaper and that's what your machine uses.

beej:

i'm not sure that your reasoning is correct, although it sounds good. i think a faster bus can handle slower ram, but a slower bus can't handle faster ram.
 

Beej

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Jan 6, 2002
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Buffy's bedroom
Originally posted by germanknee
i'm not sure that your reasoning is correct, although it sounds good. i think a faster bus can handle slower ram, but a slower bus can't handle faster ram.
My G4 400 pumped full of PC 133 doesn't seem to know that...
 

blackpeter

macrumors 6502a
Aug 14, 2001
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RAM can be a huge variable in any system, PC or Mac.

It has been my experience that if you're buying new RAM, take the time to get it from a reputiable vendor (Crucial is one - RamJet is another). ...and just get the type your machine was meant to take. If it's PC100, get PC100.

But, if you've got RAM laying around and you're the tinkering type, it never hurts to try to boost your memory. If it works, it works. Just remember that bad RAM (or RAM that isn't made for your box) can come with consequences ranging from minute to horrible.
 

Hemingray

macrumors 68030
Jan 9, 2002
2,913
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Ha ha haaa!
Originally posted by germanknee
i'm not sure that your reasoning is correct, although it sounds good. i think a faster bus can handle slower ram, but a slower bus can't handle faster ram.
Sorry, you got that backwards. A 133 bus with 66 ram in it will cause a bottleneck. DO NOT do this! But a 66 bus with 133 ram will do just fine, you'll just never get the full 133 out of the RAM. It can only run as fast as the system bus.
 

Rower_CPU

Moderator emeritus
Oct 5, 2001
11,111
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San Diego, CA
Originally posted by germanknee
i'm not sure that your reasoning is correct, although it sounds good. i think a faster bus can handle slower ram, but a slower bus can't handle faster ram.
Beej is correct. The bus dictates the speed the RAM runs at. If you're on a 100 MHz bus, the RAM will run at 100, hence PC-100 is recommended. PC-133 runs fine in 100MHz systems.
PC-100 will not run in a 133 MHZ system. This becomes crucial for people who are trying to overclock their systems. People who won't/can't change their clock multiplier will increase their front side bus for more speed. If you have crappy/slow RAM you won't get far. This is why people recommend CL2 RAM for better performance, and why people sell PC-150 RAM to overclockers who will be pushing their FSBs past 133.
Make sense?
 

Beej

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Jan 6, 2002
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Buffy's bedroom
Originally posted by Rower_CPU


Beej is correct. The bus dictates the speed the RAM runs at. If you're on a 100 MHz bus, the RAM will run at 100, hence PC-100 is recommended. PC-133 runs fine in 100MHz systems.
PC-100 will not run in a 133 MHZ system. This becomes crucial for people who are trying to overclock their systems. People who won't/can't change their clock multiplier will increase their front side bus for more speed. If you have crappy/slow RAM you won't get far. This is why people recommend CL2 RAM for better performance, and why people sell PC-150 RAM to overclockers who will be pushing their FSBs past 133.
Make sense?
Sure does. :D
 

Choppaface

macrumors 65816
Jan 22, 2002
1,187
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SFBA
512 megs of PC 133 running in my dual 500 G4 (100 mhz bus) in conjunction with another stick of 512 PC100 no problems here
 

Rower_CPU

Moderator emeritus
Oct 5, 2001
11,111
0
San Diego, CA
Re: Low Profile vs High profile

Originally posted by jaykk
What is the difference between Low Profile and High profile...
I have a TiBook g4 550 Mhz with 256 MB built-in.. i am planning to upgrade to 768 by getting a 512MB from memorytogo..which one should i choose
here is the listing
http://www.memorytogo.com/mem/modeldetail.asp?modelid=PowerBook+G4+Titanium+550+M8362LL/A

thanks in advance
Low profile refers to the size of the SO-DIMM. High profile chips won't fit in certain slots, but low profile will fit in any slot. So when it doubt, go with low profile, the price should be identical. [Ed. I checked, and "top slot only" (aka high profile) chips are lightly cheaper. I found a top slot 512 chip for $175, and a low profile for $188 from Coast to Coast Memory. They seem to be OK at resellerratings.com.]

Mac_User, where'd you go? ;) Go Aztecs!
 

germanknee

macrumors member
Jan 24, 2002
79
0
yes, i understood that slower ram in a faster bus creates a bottleneck. i just didn't relize that one could put faster ram on a slower bus. that's excellent. thank you (all) for the correction.
 

mymemory

macrumors 68020
May 9, 2001
2,495
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Miami
Re: Low Profile vs High profile

Originally posted by jaykk
What is the difference between Low Profile and High profile...
I have a TiBook g4 550 Mhz with 256 MB built-in.. i am planning to upgrade to 768 by getting a 512MB from memorytogo..which one should i choose
here is the listing
http://www.memorytogo.com/mem/modeldetail.asp?modelid=PowerBook+G4+Titanium+550+M8362LL/A

thanks in advance
I understud that hi-profile is Apple certify memory that fill Apple standards. Low profile may not meet the standards it can give some troubles when you upgrade the sys rom of your machine. I know that for a recently experience.

About two weeks ago I went to a friend of mine that has an Apple store. He asked me to brought my Pismo for an experiment. He had one low profile memory that didn't work with his pismo but later on it works with mine.

He had a 512MB ram that really was 2 256MB chips soldered togather very tight. What happen, I had sys 9 only and my rom was the old one, my friend had OSX that uses a new rom that sure reconizes more aspects of the memory (I'm sure to guaranted stability). So that is what I know about that and from 2 different sources.
 

Rower_CPU

Moderator emeritus
Oct 5, 2001
11,111
0
San Diego, CA
Re: Re: Low Profile vs High profile

Originally posted by mymemory


I understud that hi-profile is Apple certify memory that fill Apple standards. Low profile may not meet the standards it can give some troubles when you upgrade the sys rom of your machine. I know that for a recently experience.

About two weeks ago I went to a friend of mine that has an Apple store. He asked me to brought my Pismo for an experiment. He had one low profile memory that didn't work with his pismo but later on it works with mine.

He had a 512MB ram that really was 2 256MB chips soldered togather very tight. What happen, I had sys 9 only and my rom was the old one, my friend had OSX that uses a new rom that sure reconizes more aspects of the memory (I'm sure to guaranted stability). So that is what I know about that and from 2 different sources.
Sorry dude, you're way off. Read my post above about low vs. high profile RAM.
Too bad about your friend...:(
 

Beej

macrumors 68020
Jan 6, 2002
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0
Buffy's bedroom
Come to think of it, I'm pretty sure the RAM that came with my old G4 (100 MHz bus) actually came from Apple with PC 133 in it.

I think. Can anyone tell me if I'm crazy?
 

Rower_CPU

Moderator emeritus
Oct 5, 2001
11,111
0
San Diego, CA
Originally posted by Beej
Come to think of it, I'm pretty sure the RAM that came with my old G4 (100 MHz bus) actually came from Apple with PC 133 in it.

I think. Can anyone tell me if I'm crazy?
It's possible. They're mixing PC-133 and PC-100 in the new iMacs direct from Apple.