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Ram upgrade in MBP

UmaThurman

UmaThurman

macrumors regular
Original poster
Aug 1, 2006
124
0
Georgia
Hey y'all, sorry to bother y'all wit another noob question. Anyways, i've been thinking about upgrading my ram cause my overall mbp performance has gone down a little. It takes a bit longer to start up, open programs, etc. I ran the disk check thingy, and everything came back fine (i guess slowing down is natural for a computer?). So now i'm thinking about upgrading ram. Since i bought mine last november (when the core 2 duo first cam out) i've read that i can only upgrade to 3gb. So i know that there is a 1 gig stick in there, so should i buy a 1g or 2g stick? I'm not sure where to get it either, but i read in someone else's post that they recommended this site, http://eshop.macsales.com/MyOWC/Upgrades.cfm?model=258&type=Memory&TI=5522&shoupgrds=Show+Upgrades

I'm thinking about the 1g samsung stick (super cheap, 49 bucks for a stick!)? Is this easy to install?
 
sorry, i read the guide but still am a little confused i guess. I'm confused by the first part though, "All Intel Core Macs support dual channel memory access if matching modules are installed. The customary estimate is that this gives a 6% - 8% real world performance benefit. The modules do not have to be the same brand, but they do have to be the same size, speed and 'composition'. That means it is quite possible but not 100% guaranteed, that adding a 3rd party SODIMM to an Apple supplied SODIMM of the same size will make a matched pair."

So does that mean i should get apple ram to make sure 100% that is is a matched pair? I think i'll just buy a 1g stick, it seems like i won't need the 2g stick from the description. Sorry to bother y'all..
 
On a related note, when installing 3 GB (1 + 2 GB), do you know whether there is a preferred "order" for the modules? In other words, is it best to put the 2 GB module in a particular slot?
 
Nermal said:
On a related note, when installing 3 GB (1 + 2 GB), do you know whether there is a preferred "order" for the modules? In other words, is it best to put the 2 GB module in a particular slot?
Click to expand...

GOOD QUESTION!!! I really have No Idea, but I think there is No difference... and Obviously the Fact that it is "up to 3GB" must mean any other models can have "mismatched" quantities as well (ie. OK to use 1 GB and 512M together if $$ wise can't afford 2x1GB at the time).... :confused:
 
UmaThurman said:
So does that mean i should get apple ram to make sure 100% that is is a matched pair? I think i'll just buy a 1g stick, it seems like i won't need the 2g stick from the description. Sorry to bother y'all..
Click to expand...

A Samsung module from OWC will most likely make a matched pair just fine. It's just that there is no way to absolutely guarantee -- 99.5% maybe but not 100% -- that two different modules will pair.
Most modules are made with 16 chips -- If the two modules have different numbers of memory chips on them (16 chips on one vs. 8 chips on the other) then there is a higher probability that they will not pair.

There is no slot preference for RAM in the Core2Duo Macs (there is for the MacPro but that's an entirely different animal)
 
Hmm.. CanadaRam, what will that mean then if i order and install it, and then i's only 99.5% paired? If it's not a matched pair, does that mean it won't be recognized at all or does it mean that only 99.5% of that 1g stick can be used?

Also, when you said "If the two modules have different numbers of memory chips on them (16 chips on one vs. 8 chips on the other) then there is a higher probability that they will not pair. "
Is there anyway i can check to see if they will be a match before buying it?
 
UmaThurman said:
Hmm.. CanadaRam, what will that mean then if i order and install it, and then i's only 99.5% paired? If it's not a matched pair, does that mean it won't be recognized at all or does it mean that only 99.5% of that 1g stick can be used?
Click to expand...

No -- Dual Channel pairing is all or nothing. It only affects whether both modules can be addressed in the faster Dual Channel mode. It does not affect the Gb capacity of the RAM. Even if you don't have a matched pair, you will still have all of the RAM addressable, just in the slightly slower regular access mode.

What we're talking about is the probability that two modules of the same size and speed from different suppliers will match in "Composition" to allow the machine to use them in Dual Channel mode.

And what I'm saying is it is impossible to know beyond a shadow of a doubt that a given module will match the Apple module, because

1) Apple doesn't publish the criteria for matching compostition - we assume this to mean the organization of the chips on the module into rows and columns - there are several different ways to build a module.

and

2) Apple uses a number of different suppliers for RAM and doesn't publish the composition of the modules they use or even which brand is in their machines this week.

But: There is an excellent chance that two modern modules WILL match for Dual Channel access, as long as they have the same speed and number of chips on the module.
 
UmaThurman said:
Hmm.. CanadaRam, what will that mean then if i order and install it, and then i's only 99.5% paired? If it's not a matched pair, does that mean it won't be recognized at all or does it mean that only 99.5% of that 1g stick can be used?

Also, when you said "If the two modules have different numbers of memory chips on them (16 chips on one vs. 8 chips on the other) then there is a higher probability that they will not pair. "
Is there anyway i can check to see if they will be a match before buying it?
Click to expand...

Your computer will run perfectly fine with mismatched ram (ie, a 512mb and 1 gig stick to make 1.5 gigs, ect.) , you just wont get the 6-8% dual channel boost, however most people agree that its more important to have the extra ram than that very small performance increase with paired ram. I believe your computer is running in single channel mode right now anyways if all you have is ONE 1gig stick. Dual channel memory requires to for full speed.
 
Yeah, i guess it's in single channel mode cause i bought the first core 2 duo mbp in november '06. So i'm pretty sure it's a 1g stick in there.

CanadaRam, sorry to bother you again, but is there a certain way to check the # of chips on the module? And you said there is no way to check after installation if it's running in dual channel mode??? What a bummer...
 
UmaThurman said:
Yeah, i guess it's in single channel mode cause i bought the first core 2 duo mbp in november '06. So i'm pretty sure it's a 1g stick in there.

CanadaRam, sorry to bother you again, but is there a certain way to check the # of chips on the module? And you said there is no way to check after installation if it's running in dual channel mode??? What a bummer...
Click to expand...

Im'a guess there is a way, but I don't know off the top of my head. System Profiles doesn't say (I don;t think) whether the RAM is operating in single or dual channel

The only thing I have been able to find is if you are running Windows under Bootcamp, you may be able to see it during the startup, or you can download and run CPU-Z and it will report on the memory.

To check the number of chips, you have to take out the module and physically count the number of black memory chips on the module, on both sides.
 
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