5 ms·

64-bit MacBook Pro notebooks may take up to 16GB of RAM

21 points by davethenerd 15y ago

deleted 15y ago
[deleted]
hemancuso 15y ago
Well known. Here are kits for MacBook Pros: http://eshop.macsales.com/shop/memory/Apple_MacBook_MacBook_Pro/Upgrade/DDR3_1333MHz_SDRAM http://eshop.macsales.com/shop/memory/Apple_MacBook_MacBook_...
lancefisher 15y ago
I recently found out that I could upgrade my late 2008 MacBook Pro to 8GB of RAM. The specs say only 4GB will work, but soon as I found out that 8GB should work I upgraded for just $50. You need an EFI firmware update that you may have already installed. Read more: http://www.macrumors.com/2011/03/07/secret-firmware-update-unlocks-support-for-8-gb-ram-on-late-2008-notebooks/ http://www.macrumors.com/2011/03/07/secret-firmware-update-u...
kogir 15y ago
This has only ever been a chipset limitation. Not that long ago there were 64-bit capable Nvidia chipsets that could still only address 3GB of physical RAM due the way they mapped device memory into the system address space [1]. Sandy Bridge processors contain their own memory controllers that can address 16GB-32GB of RAM. True for any system they're in, as long as all channels are linked to physical DIMM slots [2]. [1] http://blogs.msdn.com/b/hiltonl/archive/2007/04/13/the-3gb-not-4gb-ram-problem.aspx http://blogs.msdn.com/b/hiltonl/archive/2007/04/13/the-3gb-n... [2] http://ark.intel.com/ http://ark.intel.com/
- pasbesoin 15y ago
  Hmm, your links imply that my old Inspiron 6400 might be able to take two 2 GB modules (the manual says it can handle a 2 GB module) and have access to something more than 2GB of addressable RAM. Anyone happen to try this with this or a similar model Dell? (The 6400 is equivalent to the 1505, IIRC. Its manual says it's limited to 2 GB of RAM.) EDIT: Answering myself, it appears it can take 2 x 2 GB sticks. The following Dell forums thread describes this, although this particular post linked claims that the configuration will disable dual channel memory access (but then again, other posters are happy and view the expansion as an improvement). http://en.community.dell.com/support-forums/laptop/f/3518/p/18322272/18445258.aspx#19007577 http://en.community.dell.com/support-forums/laptop/f/3518/p/... EDIT2: I've seen some other comments that dual channel remains enabled (with matched 2 x 2GB sticks). I guess I'll give it a go.
  - deleted 15y ago
    [deleted]
gojomo 15y ago
If I understand correctly, more RAM draws more power. Anyone have an idea of the hit to battery life caused by going to 16GB?
- dqminh 15y ago
  no, more ram means less power consumption because you are accessing hard drive less often.
  - gojomo 15y ago
    Pretty sure that's wrong except in contrived disk-heavy workloads. RAM needs power in proportion to its storage size. My 2009 MBP, which I immediately upgraded to 8GB RAM on purchase, has never come close to the stock advertised battery life. And, supposedly a reason Apple optimizes iOS devices for such small RAM sizes (sizes which are never emphasized in published descriptions) is that minimizing RAM is an important factor for their long battery life.
  - cylinder714 15y ago
    For what it's worth, the OpenBSD team is working on improved buffering for high-RAM machines: "Computers today have immense quantity of unused memory. This new software almost works, we still have some minor bugs to fix, but the results so far are incredible. On computers with 16GB of RAM we can dedicate as much as 13 GB to buffering and almost no data is read from the hard drive, everything is in the RAM. It performs even faster than SSDs. We only have to write to the disk anymore and that’s mainly for reliability reasons. I estimate we’re a year away from the whole thing working flawlessly. From this aspect the 6 month release cycle is a bit limiting." http://undeadly.org/cgi?action=article&sid=20111018061633 http://undeadly.org/cgi?action=article&sid=2011101806163...
    - gonzo 15y ago
      seriously, you think OpenBSD invented the buffer cache?
- steve8918 15y ago

21 points by davethenerd 15y ago

deleted 15y ago

[deleted]

Well known. Here are kits for MacBook Pros: http://eshop.macsales.com/shop/memory/Apple_MacBook_MacBook_Pro/Upgrade/DDR3_1333MHz_SDRAM http://eshop.macsales.com/shop/memory/Apple_MacBook_MacBook_...

lancefisher 15y ago

I recently found out that I could upgrade my late 2008 MacBook Pro to 8GB of RAM. The specs say only 4GB will work, but soon as I found out that 8GB should work I upgraded for just $50. You need an EFI firmware update that you may have already installed. Read more: http://www.macrumors.com/2011/03/07/secret-firmware-update-unlocks-support-for-8-gb-ram-on-late-2008-notebooks/ http://www.macrumors.com/2011/03/07/secret-firmware-update-u...

kogir 15y ago

This has only ever been a chipset limitation. Not that long ago there were 64-bit capable Nvidia chipsets that could still only address 3GB of physical RAM due the way they mapped device memory into the system address space [1]. Sandy Bridge processors contain their own memory controllers that can address 16GB-32GB of RAM. True for any system they're in, as long as all channels are linked to physical DIMM slots [2]. [1] http://blogs.msdn.com/b/hiltonl/archive/2007/04/13/the-3gb-not-4gb-ram-problem.aspx http://blogs.msdn.com/b/hiltonl/archive/2007/04/13/the-3gb-n... [2] http://ark.intel.com/ http://ark.intel.com/

pasbesoin 15y ago
Hmm, your links imply that my old Inspiron 6400 might be able to take two 2 GB modules (the manual says it can handle a 2 GB module) and have access to something more than 2GB of addressable RAM. Anyone happen to try this with this or a similar model Dell? (The 6400 is equivalent to the 1505, IIRC. Its manual says it's limited to 2 GB of RAM.) EDIT: Answering myself, it appears it can take 2 x 2 GB sticks. The following Dell forums thread describes this, although this particular post linked claims that the configuration will disable dual channel memory access (but then again, other posters are happy and view the expansion as an improvement). http://en.community.dell.com/support-forums/laptop/f/3518/p/18322272/18445258.aspx#19007577 http://en.community.dell.com/support-forums/laptop/f/3518/p/... EDIT2: I've seen some other comments that dual channel remains enabled (with matched 2 x 2GB sticks). I guess I'll give it a go.
- deleted 15y ago
  [deleted]

gojomo 15y ago

If I understand correctly, more RAM draws more power. Anyone have an idea of the hit to battery life caused by going to 16GB?

dqminh 15y ago
no, more ram means less power consumption because you are accessing hard drive less often.
- gojomo 15y ago
  Pretty sure that's wrong except in contrived disk-heavy workloads. RAM needs power in proportion to its storage size. My 2009 MBP, which I immediately upgraded to 8GB RAM on purchase, has never come close to the stock advertised battery life. And, supposedly a reason Apple optimizes iOS devices for such small RAM sizes (sizes which are never emphasized in published descriptions) is that minimizing RAM is an important factor for their long battery life.
- cylinder714 15y ago
  For what it's worth, the OpenBSD team is working on improved buffering for high-RAM machines: "Computers today have immense quantity of unused memory. This new software almost works, we still have some minor bugs to fix, but the results so far are incredible. On computers with 16GB of RAM we can dedicate as much as 13 GB to buffering and almost no data is read from the hard drive, everything is in the RAM. It performs even faster than SSDs. We only have to write to the disk anymore and that’s mainly for reliability reasons. I estimate we’re a year away from the whole thing working flawlessly. From this aspect the 6 month release cycle is a bit limiting." http://undeadly.org/cgi?action=article&sid=20111018061633 http://undeadly.org/cgi?action=article&sid=2011101806163...
  - gonzo 15y ago
    seriously, you think OpenBSD invented the buffer cache?
steve8918 15y ago