From 2.5 to 4 GB RAM - Do I need exact same model?

Zebbe08

macrumors newbie
Original poster
Feb 12, 2008
6
0
Hi,
I'm considering maxing out the RAM on my SR MacBook. I currently have one of the stock 512 MB sticks and one 2 GB Kingston Apple-branded stick, model number KTA-MB667/2G.

Now, I could get another one of the 2 GB Kingston's with the exact same model number, but for about 15% less (not much, I know, but enough for me to consider it) I could get a 2 GB Kingston ValueRAM module , model number KVR667D2S5/2G. The question is if there is any downside to this?

Thanks,
Sebastian
 

Zebbe08

macrumors newbie
Original poster
Feb 12, 2008
6
0
It is recommend that you have say 2 x 1GB or 2 x 2GB of the same make for dual channel support
I'm not sure if you noticed or maybe I just misinterpreted your post, but the two sticks I'm considering are from the same make - Kingston. But different model numbers.
 

Mal

macrumors 603
Jan 6, 2002
6,253
17
Orlando
It's not a big deal. The benefits are in the 4-5% range for two of the exact same over two completely different ones, but you won't suffer much of a hit from not having two manufactured consecutively (which is considered the absolute best option). The benefits from having more RAM will greatly outweigh the disadvantages of them not being identical.

jW
 

Neil321

macrumors 68040
I'm not sure if you noticed or maybe I just misinterpreted your post, but the two sticks I'm considering are from the same make - Kingston. But different model numbers.
Ar sorry i misread your post as i thought you wanted to install 1 x 512mb & 1 x 2GB, anyways just reread your post and your good to go,but still its recommended you buy matching pairs
 

Zebbe08

macrumors newbie
Original poster
Feb 12, 2008
6
0
It's not a big deal. The benefits are in the 4-5% range for two of the exact same over two completely different ones, but you won't suffer much of a hit from not having two manufactured consecutively (which is considered the absolute best option). The benefits from having more RAM will greatly outweigh the disadvantages of them not being identical.

jW
OK. So, based on your post here you could make a list:

Best

1. Two sticks w/ same model number manufactured consecutively.
2. Same, but not manufactured consecutively.
3. Same manufacturer, same specs, different model number.
4. Different manufacturer, same specs.

Worst


The difference between 1 and 4 is about 4-5%. But is there a smaller difference for 1-2 and 1-3?

What I'm trying to say is, is it possible to get dual channel performance in any other way than having exactly the same sticks?
 

MacUser2525

macrumors 68000
Mar 17, 2007
1,811
207
Canada
What I'm trying to say is, is it possible to get dual channel performance in any other way than having exactly the same sticks?
You don't need them to be the exact model for them to run in dual channel mode just the same size modules, now it is definitely best to have a matched pair to ensure the greatest chance at compatibility but its not a absolute requirement for it to work.
 

neiltc13

macrumors 68040
May 27, 2006
3,115
6
Before you go spending money on RAM, fire up the MOST INTENSIVE thing you use your computer for. In my case, that's running Photoshop and Dreamweaver at the same time along with my RSS reader, Adium, Safari and iTunes, along with my FTP application and little trinkets like GMail notifier and Last.fm.

Once you've got all your processes running, go to Applications -> Utilities -> Activity Monitor.

In there click the "System Memory" tab and then look at the "used" part at the bottom. That's the amount of RAM that your computer is actually using at that moment.

In my case it's 1.54GB. I don't know what you use your computer for but there are few applications which will put more of a strain on your computer than the sort of thing I'm doing.

If this figure is less than the amount of memory you currently have then you will be flat out wasting your money by buying more RAM.
 

Mal

macrumors 603
Jan 6, 2002
6,253
17
Orlando
OK. So, based on your post here you could make a list:

Best

1. Two sticks w/ same model number manufactured consecutively.
2. Same, but not manufactured consecutively.
3. Same manufacturer, same specs, different model number.
4. Different manufacturer, same specs.

Worst


The difference between 1 and 4 is about 4-5%. But is there a smaller difference for 1-2 and 1-3?

What I'm trying to say is, is it possible to get dual channel performance in any other way than having exactly the same sticks?
Actually, I believe the last on the list (4-5% from the top) would be two sticks of a different capacity from different manufacturers, though the same specs. That's assuming I'm remembering correctly.

jW
 

MacUser2525

macrumors 68000
Mar 17, 2007
1,811
207
Canada
Actually, I believe the last on the list (4-5% from the top) would be two sticks of a different capacity from different manufacturers, though the same specs. That's assuming I'm remembering correctly.

jW
Your not the modules need to be equal eg. 2gb with 2gb preferably with the same rated speed and timings, same manufacturer and model you have hit the jackpot. Modules of unequal size will run in single channel mode and as Neil321 mentions if the OP is not hitting swap on any regular basis then he really does not need to upgrade and if using less than 2gb of his ram may want to consider a matched 1gb pair to get the extra speed of dual channel if he feels he needs it.