Register FAQ / Rules Forum Spy Search Today's Posts Mark Forums Read
Go Back   MacRumors Forums > Apple Hardware > Notebooks > MacBook

Reply
 
Thread Tools Search this Thread Display Modes
Old Feb 16, 2011, 07:38 PM   #1
3paulx
macrumors member
 
Join Date: Feb 2009
Ram upgrade: DDR2 667MHz to 800MHz?

Hi, im planning change my white MacBook's ram from DDR2 2gb to 4gb but the stock Ram is 667MHz and I might replace it with DDR2 4gb 800MHz from a Macbook Pro.....is that ok? any problems/complications with peroformance if i do that? Thanks!

Peace!
__________________
bicMAC, fries and coke. Oh and APLLE pie too!
3paulx is offline   0 Reply With Quote
Old Feb 17, 2011, 02:54 AM   #2
AndyK
Contributor
 
AndyK's Avatar
 
Join Date: Jan 2008
Location: England.
http://www.crucial.com/

Use their memory scanner & it'll tell you what the best upgrade choices are for your machine.
__________________
Search before you post.
AndyK is offline   0 Reply With Quote
Old Feb 17, 2011, 03:09 AM   #3
AF08
macrumors member
 
Join Date: Jun 2010
Location: Huntington Beach
should work

Quote:
Originally Posted by 3paulx View Post
Hi, im planning change my white MacBook's ram from DDR2 2gb to 4gb but the stock Ram is 667MHz and I might replace it with DDR2 4gb 800MHz from a Macbook Pro.....is that ok? any problems/complications with peroformance if i do that? Thanks!

Peace!
the 800mhz ram will slow down to 667mhz
__________________
AF08 is offline   0 Reply With Quote
Old Feb 17, 2011, 07:24 AM   #4
logana
macrumors 65816
 
logana's Avatar
 
Join Date: Feb 2006
Location: Scotland
Quote:
Originally Posted by AF08 View Post
the 800mhz ram will slow down to 667mhz
Not quite correct - the later nVidea white MacBooks have a higher bus speed and can run the 800MHz at that speed although Apple fitted some with the slower PC5300 ram.

But we don't know what MacBook AF08 has....
__________________
MacBook 7,1 - 2.4GHz 8GB 500GB, 32GB iPod Touch 4G
logana is offline   0 Reply With Quote
Old Feb 17, 2011, 07:41 AM   #5
blackburn
macrumors 6502a
 
blackburn's Avatar
 
Join Date: Feb 2010
Location: Where Judas lost it's boots.
Macs with 667 pre-fitted in them will refuse to boot with 800 MHz ram.
It's due to the spd in the ram modules. (It boots only if one is 667)
There is a speed table that can only carry 3 different speeds (JDEC ddr2 offical spec), so let me explain:

The 667 module has 400 - 533 and 667 programmed in it.

But the 800 module has 400 - 533 - 800, so when the macbook checks for the 667 speed and doesnt find it, it wont boot.
__________________
Lenovo ThinkPad + Nexus 7 (2nd Gen)
blackburn is offline   0 Reply With Quote
Old Feb 18, 2011, 03:11 AM   #6
logana
macrumors 65816
 
logana's Avatar
 
Join Date: Feb 2006
Location: Scotland
Quote:
Originally Posted by blackburn View Post
Macs with 667 pre-fitted in them will refuse to boot with 800 MHz ram.
It's due to the spd in the ram modules. (It boots only if one is 667)
There is a speed table that can only carry 3 different speeds (JDEC ddr2 offical spec), so let me explain:

The 667 module has 400 - 533 and 667 programmed in it.

But the 800 module has 400 - 533 - 800, so when the macbook checks for the 667 speed and doesnt find it, it wont boot.
That cannot be right either - I spent yesterday checking some 2GB PC6400 ram modules. I was using a MacBook 2,1 (2GHz Core 2 originally fitted with PC5300 ram). The MacBook booted fine with a single PC6400 module (800MHz) and the memory tested fine and System Profiler reported it as 667MHz DDR2......

The MacBook 3,1 and 4,1 models (late 2007 to 2008) won't boot with a single PC6400 chip in them but the MacBook 5,2 (nVidea white non-unibody) will.
__________________
MacBook 7,1 - 2.4GHz 8GB 500GB, 32GB iPod Touch 4G
logana is offline   0 Reply With Quote
Old Feb 18, 2011, 04:20 PM   #7
3paulx
Thread Starter
macrumors member
 
Join Date: Feb 2009
thanks for the reply guys!
__________________
bicMAC, fries and coke. Oh and APLLE pie too!
3paulx is offline   0 Reply With Quote
Old Feb 18, 2011, 06:55 PM   #8
blackburn
macrumors 6502a
 
blackburn's Avatar
 
Join Date: Feb 2010
Location: Where Judas lost it's boots.
Quote:
Originally Posted by logana View Post
That cannot be right either - I spent yesterday checking some 2GB PC6400 ram modules. I was using a MacBook 2,1 (2GHz Core 2 originally fitted with PC5300 ram). The MacBook booted fine with a single PC6400 module (800MHz) and the memory tested fine and System Profiler reported it as 667MHz DDR2......

The MacBook 3,1 and 4,1 models (late 2007 to 2008) won't boot with a single PC6400 chip in them but the MacBook 5,2 (nVidea white non-unibody) will.
Well i don't own any of these macbooks, just what I've read. Since my unibody works with faster ram but overheats, It must be on model by model basis. (I don't know if there is an table/post with that usefull information)
__________________
Lenovo ThinkPad + Nexus 7 (2nd Gen)
blackburn is offline   0 Reply With Quote

Reply
MacRumors Forums > Apple Hardware > Notebooks > MacBook

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Similar Threads
thread Thread Starter Forum Replies Last Post
Resolved: 800mhz and 667mhz RAM not compatible Mac Pro 3,1? NOTNlCE Mac Pro 13 Oct 12, 2013 06:17 PM
iMac 24" 3.06 Core 2 Duo DDR2 800Mhz machine compatible with Mtn Lion? Doctorsti iMac 6 Aug 1, 2012 10:25 AM

Forum Jump

All times are GMT -5. The time now is 12:29 AM.

Mac Rumors | Mac | iPhone | iPhone Game Reviews | iPhone Apps

Mobile Version | Fixed | Fluid | Fluid HD
Copyright 2002-2013, MacRumors.com, LLC