Macbook Pros: 64bit?

Discussion in 'MacBook Pro' started by Firanide, Oct 16, 2008.

  1. Firanide macrumors member

    Joined:
    Mar 4, 2007
    Location:
    Canadia
    #1
  2. shoppy macrumors 6502a

    Joined:
    Mar 4, 2007
    Location:
    Hants
    #2
    They have been 64 bit for a while now. I think since they went C2Duo.
     
  3. robbieduncan Moderator emeritus

    robbieduncan

    Joined:
    Jul 24, 2002
    Location:
    London
    #3
    There is a difference between the chipset and the CPU. The CPU is 64-bit. It seems the chipset is 32-bit. The means that you can only have 4Gb of RAM, but you can run 64-bit software.
     
  4. shoppy macrumors 6502a

    Joined:
    Mar 4, 2007
    Location:
    Hants
    #4
    My apologies, I guess you leran something new every day.
     
  5. Tex-Twil macrumors 68020

    Tex-Twil

    Joined:
    May 28, 2008
    Location:
    Europe
    #5
  6. Firanide thread starter macrumors member

    Joined:
    Mar 4, 2007
    Location:
    Canadia
    #6
    Alright, thanks for clarifying that.

    So...what does that mean when Snow Leopard comes out? Will we still see the same performance boost of going all 64-bit by still having a 32-bit chipset?

    Haha, I do believe that's some good ol' eye-trickery there. In reality (at least, according to Apple), it's not significantly larger. A quarter inch wider, a little bit deeper, but 0.05" thinner!
     
  7. nephilim7 macrumors regular

    Joined:
    Jun 13, 2008
    #7
    this is incorrect.
     
  8. Firanide thread starter macrumors member

    Joined:
    Mar 4, 2007
    Location:
    Canadia
    #8
    Thanks...for your input?

    Mind correcting him if he's incorrect?
     
  9. nephilim7 macrumors regular

    Joined:
    Jun 13, 2008
    #9
    I'll leave it as an exercise to the reader, takes 5 minutes to learn about the chipsets used in the macbook pro.
     
  10. robbieduncan Moderator emeritus

    robbieduncan

    Joined:
    Jul 24, 2002
    Location:
    London
    #10
    In what way? If the chipset (the NVidia 9400M combined north/south bridge and GPU) has a 32-bit memory controller then you will be limited to 4Gb of RAM. The CPU and OS should still be able to run in 64-bit mode: the MMU will be translating addresses from VM, per-process space to actual physical RAM space anyway.

    What performance boost? There is nothing intricately faster about 64-bit. Sure you get a few extra registers on the CPU but that's not going to make a huge difference. Unless the process can use more than 4Gb of address space it gains very little by being 64-bit...
     
  11. nephilim7 macrumors regular

    Joined:
    Jun 13, 2008
    #11
    *if*

    *should*

    =/

    no one would make a 32 bit memory controller now any more than they would release a 32 bit CPU. The last mbp to have a 32 bit controller was napa.

    penryn runs 8g fine in linux. and 6g fine in OSX.
     
  12. robbieduncan Moderator emeritus

    robbieduncan

    Joined:
    Jul 24, 2002
    Location:
    London
    #12
    On an Intel chipset that has a >32bit memory controller. NVidia do not appear to have provided any details on the memory controller on their website (I checked). It says it's "128-bit" but this is the width of the data bus, not the address bus. So far only one site I have seen has said anything on this and they claim it's 32-bit. So there is evidence for this, whereas your claims that I am flat-out wrong are based on speculation...
     
  13. nephilim7 macrumors regular

    Joined:
    Jun 13, 2008
    #13
    and you are saying you are flat out right based on speculation.

    do you really think nvidia would make a 32 bit memory controller... after intel got beaten sideways for this 2 years ago? You need 64bit addressing to handle 4G with all the baggage of the x86 mess. unless you lie.. which is what some manufacturers did.
     
  14. robbieduncan Moderator emeritus

    robbieduncan

    Joined:
    Jul 24, 2002
    Location:
    London
    #14
    I disagree: I am basing my answers on a public stated declaration on a reasonably trusted site that is linked at the top of this thread.

    I view this entire thread to be under the assumption that they are correct. If you disagree with this fact you should have quoted the original post/some text from that site and claimed they were wrong rather than attacking me where I said "It seems the chipset is 32-bit". At no point have I said 100% that the chipset it is 32-bit: I have always hedged my statements to show that I am working on the assumption that the article under discussion is correct. This is in direct contradiction to you; you have always claimed, flat-out, that it's >32-bit without any hedging of your language and no proof. I see little point in continuing this discussion...
     
  15. nephilim7 macrumors regular

    Joined:
    Jun 13, 2008
    #15
    ifixit's statements are wrong. They say something about 'they are sticking to 32 bit chipsets in their notebook line so you are stuck with 4G' which was true a few years ago, but is not true about early 2008.

    This does not say that the current chipsets (late 2008) are not capable or are capable.. voting on a rabbits sex doesn't do anything but annoy the rabbit. Apple knows that penryn mbps can support 8G in 10.6.. they have to know this, they designed the things. Would they then, as they redesign their entire line choose to limit it to 4G? Perhaps.. but I think it's unlikely.

    This isn't an attack, it's another opinion.

    also properly written video filters, DSP and things like rendermans prman running RSL get a fairly significant speed boost in 64 bit. Not exactly pedestrian stuff, but you're not supposed to be doing pedestrian stuff on a macbook pro.
     
  16. dukebound85 macrumors P6

    dukebound85

    Joined:
    Jul 17, 2005
    Location:
    5045 feet above sea level
    #16
    can you please back up your claims with links or something? so far you are just saying they are wrong where there is an article in this page saying the opposite. not gonna lie, but im taking the articals word for it atm
     
  17. aleksandra. macrumors 6502a

    Joined:
    Sep 13, 2008
    Location:
    Warsaw, Poland
    #17
    I wonder where did iFixit got this information? If they have MCP79 datasheet, it'd be nice if they told us so. As of now there's no information publicly available about this chip... I think previous motherboards from NVIDIA used HyperTransport, which operates differently than usual FSB? I don't know much about it though, and it's generally hard to find reliable information about anything NVIDIA-related.

    Anyway, nForce 7xx series apparently supported up to 8GB RAM with Intel CPUs (although this is taken from Wikipedia, so...), and MCP7A is supposedly next version of it, and since MCP79 is the mobile version of MCP7A... I simply find it hard to believe that NVIDIA would downgrade its chips and Apple would use them so close to Snow Leopard's release. Then again, they did insist Santa Rosa MBP can't use more than 4GB RAM, even though they seem to work flawlessly with 6GB (though have issues with 8GB).
     
  18. nephilim7 macrumors regular

    Joined:
    Jun 13, 2008
    #18
    logic and reason don't rely on convincing you or anyone on anything. You have the information to make your own call available to you.

    My claim that the early 2008s can support more than 4G and actually use it, is substantiated in this monster thread...

    http://forums.macrumors.com/showthread.php?t=573906&highlight=8G+mem

    ifixit said that 'apple is still using 32 bit memory controllers', this is incorrect, and leads me to believe they don't really know.
     
  19. nephilim7 macrumors regular

    Joined:
    Jun 13, 2008
    #19
    There was a time when intel was getting a lot of flack about the memory controller issues, I can see how someone that hasn't been keeping up with intels mobile line would make the mistake of assuming that it is still the case.
     
  20. robbieduncan Moderator emeritus

    robbieduncan

    Joined:
    Jul 24, 2002
    Location:
    London
    #20
    There is an obvious way to test this: if one of the numerous people with these new machines could just try it with more than 4Gb of RAM...

    Personally I'd be very happy if they support more. Whilst I'm not in the market right now I find the 2Gb hard limit of my MBP very annoying and when I replace it I'd certainly want more than 4Gb.
     
  21. nephilim7 macrumors regular

    Joined:
    Jun 13, 2008
    #21
    hmm after reading that thread over (I had a lot of participation in the testing) I noticed that I made a mistake in saying 8G is confirmed working in snow leopard. It was 6G that worked in snow leopard, and 6G works in 10.5 as well.

    I don't have snow leopard to test with, I have 8G and it runs fine in linux, but linux isn't doing a lot of wacky PAE shifting which leopards kernel seems to be doing, which could account for the 8G/6G mess.

    also as a note to future readers, if you have a new machine and access to either 6g or 8g of memory I encourage you to check out the thread linked above and run the app that is on around page 4? It allocates and actually uses 1 gig of memory per instance and is an easy way to test your machine.
     
  22. nephilim7 macrumors regular

    Joined:
    Jun 13, 2008
    #22
    though it would surprise me if apple made nvidia take a step backwards, secretly I hope it as it would increase the value of my penryn... though that begs the question of what mbp would I replace it with?
     
  23. aleksandra. macrumors 6502a

    Joined:
    Sep 13, 2008
    Location:
    Warsaw, Poland
    #23
    I don't know where iFixit and AnandTech get their information, but according to the comparison from here: http://www.anandtech.com/mb/showdoc.aspx?i=3432 it is (chip - memory controller):

    AMD 780G - N/A
    Intel G45 - 2 x 64-bit DDR2/DDR3 channels
    NVIDIA GeForce 9400 - 2 x 64-bit DDR2/DDR3 channels
    NVIDIA GeForce 9300 - 2 x 64-bit DDR2/DDR3 channels
    NVIDIA GeForce 8200 - N/A

    These are desktop motherboards, but it should be similar for mobile version.
     
  24. robbieduncan Moderator emeritus

    robbieduncan

    Joined:
    Jul 24, 2002
    Location:
    London
    #24
    That refers to the data bus, not the address bus. 2x64=128-bit as stated by NVidia on their specs page. Even my distinctly 32-bit CD MBP uses 64-bit memory in this sense...
     
  25. Nipz macrumors 65816

    Nipz

    Joined:
    Nov 1, 2006
    Location:
    UK
    #25
    I rang apple to finally find the true answer...

    They took my number and are going to ring me back :) will post what they say!
     

Share This Page