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So can you use 4GB in a 2.16Ghz Core2 Duo or not?

C

CMD is me

macrumors 6502
Original poster
Dec 7, 2006
401
0
Sorry to post another 3 vs 4GB RAM questions but this has me stumped (this is specific to the Core2 Duo)...

I read (here) that the Core2 Duo chips can see up to 3.3GB with 2x2GB modules. I have a 2.16 (late 06). However trying to buy a matched pair online I'm being told 2x2GB modules may not work right in the 2.16, only the 2.2+. Huh? Won't what works in the 2.2 also work in the 2.16 only the 2.16 will show 3.3GB? The price difference is only $25. So why not get a matched pair and extra RAM? Is this a case of the sales guy won't go off the spec sheet?

According to OWC that can increase the performance 50% during heavy loads (see the HOG test results)!

Additionally the guy said my system USE to be on their sheet as able to use 2x2GB however they have since changed that. Huh? The guys at OWC usually know their stuff.
 
Core 2 Duo machines that are not Santa Rosa can recognize a potential 3.3 GB ....the top 700 MB is wasted, so the practical maximum is 3 Gb . This is a hardware limitation.

With 4 GB installed, these machines will report 4 GB in System Profiler, but the operating system will only use 3.3 GB.

To sum all that up yes you can install 4GB of RAM but there isn't a huge benefit of just having the 3GB installed. The part about "not working right" is that you lose the top 700MB.....

Hopefully that help you...
 
Thanks. That's what I thought. OWC's test on matched pairs (see above link) shows a pretty big performance gain in Photoshop when 50% of the RAM is used elsewhere -- 169s compared to 98s! If that is true in real world usage (I typically do have 10 apps open at once), then it is a much larger benefit than the 3-5% increase I've read previously.
 
I have 4GB of Crucial memory installed in my C2D 2.16 White iMac running 10.5.1. About this Mac reports 4GB but Activity Monitor has never show over 3GB. I expected it to show 3.3 GB like OWC said it will. Comments?
 
I don't see 3.3. gb

I got 4gb for the 2.16ghz Imac and, sure enough, it only sees 3gb. Not 3.3 gb, either...
 
It's been discussed here
https://forums.macrumors.com/threads/377498/

Conclusion: pre-santa rosa boards cannot USE more than 3.3 gb of ram, although in practical use it's actually limited to 3gb (it might REPORT 4gb of ram, but can't use all of it due to hardware limitation), no matter what OS you use.
 
But is it not more beneficial to have the dual channel memory?

Therefore a 2x2GB will show a performance increase over a 1x1GB + 1x2GB?

This situation doesnt apply to me Im just trying to help other people in this situation!
 
heatmiser said:
Eh? How is there a 4gb boost if you're using 3gb?
Click to expand...

Dual channel. I lost dual channel when i used 1x2GB + 1x1GB. It lagged a lot of stuff, especially the eye candy in Leopard. After I switched to 2x2GB, that lag went away, my FPS in certain games went up, I can switch between windows without any problem or delay, even got my start up (pressing button to log on screen) in about 6-8 seconds.
 
ayeying said:
Dual channel. I lost dual channel when i used 1x2GB + 1x1GB. It lagged a lot of stuff, especially the eye candy in Leopard. After I switched to 2x2GB, that lag went away, my FPS in certain games went up, I can switch between windows without any problem or delay, even got my start up (pressing button to log on screen) in about 6-8 seconds.
Click to expand...

I had no idea it made that much of a difference. Thanks! I guess I'll keep waiting for the 2x2gb prices to drop instead of buying a 1x2gb stick now.
 
heatmiser said:
I had no idea it made that much of a difference. Thanks! I guess I'll keep waiting for the 2x2gb prices to drop instead of buying a 1x2gb stick now.
Click to expand...

I didn't believe it made that much of a difference either. I was quite amazed with the boost. I only upgraded to 4GB in the first place because I saw a good sale for 2x2GB, so I just took out the old 2GB in the macbook and gave it to my dad's iMac, upping his system from 2GB to 3GB.
 
Ditto... running 2 x 2GB is noticeably quicker than 1 x 2 and, of course, 1 x 1. I've run every configuration possible and for the minor cost, 2 x 2 is worth it if running multiple apps.
 
MBP C2D Napa and 4GB RAM Recognized!

Running Tiger 10.4.11 with 4GB RAM:

About This Mac: 4GB
System Profiler: 4GB
Activity Monitor: 3GB

Running Leopard 10.5.0 with 4GB RAM:

About This Mac: 4GB
System Profiler: 4GB
Activity Monitor: 4GB

Leopard 10.5.0 also updated pre-N Wireless Network Adapter to (802.11 a/b/g/n) which can be verified under Network Utility.

Apple must have done some improvement in Leopard to take advantage of full 4GB memory addressing. So much about 945PM (Napa Chipset) hardware limitation from Intel and Apple marketing team!
 
HFU said:
Running Tiger 10.4.11 with 4GB RAM:

About This Mac: 4GB
System Profiler: 4GB
Activity Monitor: 3GB

Running Leopard 10.5.0 with 4GB RAM:

About This Mac: 4GB
System Profiler: 4GB
Activity Monitor: 4GB

Leopard 10.5.0 also updated pre-N Wireless Network Adapter to (802.11 a/b/g/n) which can be verified under Network Utility.

Apple must have done some improvement in Leopard to take advantage of full 4GB memory addressing. So much about 945PM (Napa Chipset) hardware limitation from Intel and Apple marketing team!
Click to expand...

You need to read the thread referenced in #7. Been there, done that.
 
HFU said:
You are right! 3.3GB is the max usable memory space for pre-SR MBP. Thanks for the clarification.
Click to expand...

Why, why, why do you say 3.3 GB??

It is only 3 GB.

This is like the third time at least in this very thread that this has been repeated. :eek:
 
macrumorino said:
Why, why, why do you say 3.3 GB??

It is only 3 GB.

This is like the third time at least in this very thread that this has been repeated. :eek:
Click to expand...

my system uses 3.3. yours must not. RELAX it's okay. things are different sometimes. you have repeated yourself three times too. it's not a huge deal man.
 
macrumorino said:
Can you prove that, please?
Click to expand...

i don't need to prove anything. this has been stated numerous times. why are you getting so bent out of shape about this?
and you said your using an iMac. i'm using a macbook. i'm not techno-savey but could this possibly be why your not seeing your full 3.3gb.
and at the end of the day.. does it REALLY matter? are you going to sleep any less because of this?
 
LeftoverCrack said:
i don't need to prove anything. this has been stated numerous times. why are you getting so bent out of shape about this?
and you said your using an iMac. i'm using a macbook. i'm not techno-savey but could this possibly be why your not seeing your full 3.3gb.
and at the end of the day.. does it REALLY matter? are you going to sleep any less because of this?
Click to expand...

Just like I thought, you have nothing to contradict what I can observe.

The rest of your comment is a bit of a waste.
 
macrumorino said:
Just like I thought, you have nothing to contradict what I can observe.

The rest of your comment is a bit of a waste.
Click to expand...

oh my. can you not read all the other people stating this? and the Wiki that states this? what is wrong with you? why are you so set on proving this? what are you trying to accomplish??
in all 6 of your posts on this entire website you have tried to prove 3gb over 3.3gb. that is the only thing you have said.
over and over again.
why? answer me that. WHY?
 
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