Jump to content

Adding RAM


exekutive
 Share

12 posts in this topic

Recommended Posts

Lately I've been finding that I am waiting a lot for things like video processing, multi-tasking, etc. so I want to upgrade, but I want to know all of my options first.

 

I know there have been posts about RAM upgrades, but none that answer everything I need to know. I hope there's someone out there with enough expertise to answer a few specific questions.

 

This is what I understand (and please correct me if I'm wrong):

1. Hardware limitation is 3GB total. (4GB for the Core 2 Duos)

2. Slots support 512MB & 1GB SODIMMs (& 2GB for the Core 2 Duos)

3. Slots need to have matching RAM to take advantage of dual channels (increased access speed)

4. Operating system will only see 3GB (for both Core 1 and 2?)

 

This begs the questions:

- How much of a difference do the dual channels make?

 

The Apple store gives you the option to buy your MBP with 3GB installed, but I take it that this configuration is slower than the 2GB. Does the increased performance of that extra 1GB make up for that lost throughput of the dual channel feature? It would seem like pretty useless technology that the hardware supports 4GB of storage, yet realistically you can only use HALF of it to it's full extent.

 

Why aren't the 2GB modules available from the Apple store?

What if you installed 2x2GB? Would you then be able to use 3GB of it AND have the dual channel access?

Will future versions of MacOS be able to use ALL 4GB?

 

Also, Apple wants too much $$$ for their RAM. Is 3rd party RAM worth getting?

 

Thanks!

Joe

 

Macbook Pro 15" 2.16 GHz Core Duo Mac OS X (10.4.8)

Link to comment
Share on other sites

you're on the right track, but here's the situation as i understand it:

 

Core Duo MBPs can only support 2Gb RAM, in a 2x1Gb configuration. They do NOT support 3Gb.

 

Core 2 Duo MBPs can support 3Gb RAM, in a 1x1Gb and 1x2Gb configuration. As you correctly surmise, this will not allow dual-channel operation, and will thus be slightly slower.

 

My own experiments with my 1.83Ghz Core Duo MacBook Pro indicate that dual-channel DOES make a noticeable difference, contrary to popular myth. I ran with 1.5Gb and acheived a geekbench score of around 150. Upgrading to 2Gb raised my geekbench to 160, but more importantly 'felt' much faster.

 

Since you, like me, have a Core Duo MBP, I'd suggest you pick up two 1Gb sticks and be happy in dual-channel land. Oh, and once you do, please PM me your Geekbench score - i'd be interested to know how much difference there is between our machines :)

Link to comment
Share on other sites

But how are the intel core dual 2.0 gh with 1gb and 500mb ram dealing with programs? I mean I have a hackintosh (ok it is hacked version of mac and does not work the way it should have) an 1gh ram and the usage of it is 78% just with itunes and safari. And the ram problem even increases when I install more programs.

What I am trying to ask here is that how do the mac computers deal with ram?

Link to comment
Share on other sites

Munky,

What is your geekbench score actually measuring? Because adding more RAM to your system will make it feel faster regardless of whether it's using dual channels or not.

 

I did some research and purportedly the Macbook Pros use the Intel 945 family of chipset.

 

I checked Intel's specsheet on it:

http://download.intel.com/design/mobile/da...ts/30921903.pdf

 

Under processor support:

"32-bit interface to address up to 4 GB of memory"

Under system memory support:

"Maximum Memory supported: up to 4 GB at 400, 533 and 667 MHz"

 

Indeed, according to the binary system 32 bits can address numbers up to 4GB:

2^32=4,294,967,296

 

Evidently, chipset has a mapping limitation which limits it to 3GB, which still doesn't explain the 2GB limit on the Core I Duos.

 

Also, interestingly, that same specsheet says:

"256MB, 512MB and 1GB memory technologies supported"

So what about the 2GB sticks the C2D MBPs come with?

 

Further, the website here

http://www.anandtech.com/printarticle.aspx?i=2740

claims that using a dual channel memory configuration provides no advantage whatsoever over a single channel config of the same capacity, due to the FSB bottleneck.

Link to comment
Share on other sites

  • 2 weeks later...

So I ordered the 1GB stick from Apple and everything is hunky dory. I noticed the difference in performance right away.

One thing to mention though, is what I received from Apple was simply Micron brand RAM. You can get the exact same product from a 3rd party vendor and save some bucks. Just match up the part numbers. Cheers.

Link to comment
Share on other sites

  • 2 weeks later...
The next macs will be 64 bit and will allow for more than 3 GB of ram. I think the 3 GB is also a limitation on the current mobile chipset from Intel along with SODIMMS.

Core 2 Duo chips are 64Bit already, to utilise the full 4GB from a 2+2 setup should only need an upgrade to the OS (and possibly the EFI firmware)

Link to comment
Share on other sites

I realize this is an older thread, but I'm in a similar situation. I too have a 1.83GHz MacBook Pro currently with the stock 512MB RAM, and I'm looking at adding more. However, two 1GB sticks are out of my price range at the moment. Infact even a single 1GB stick is kind of pushing it. So my question to you guys is should I go with a second 512MB stick, or pay more than twice that for a 1GB stick? With the whole dual channel thing, would there be that much of a difference?

Link to comment
Share on other sites

Ram is 120 UK Pounds from Apple I have been finding it for as little as 50 Pounds.. Anyone know Where to Get some Samsung Ram for a C2D MBP in the UK. Id rather use the same brand to keep things Sweet and Avoid Probs. If I can find the right brand Ill Go Elsewhere instead of going to Apple for the Ram.

Link to comment
Share on other sites

 Share

×
×
  • Create New...