Quick question: will increasing my RAM decrease the physical heat when running Fusion

Discussion in 'MacBook Pro' started by itwasepic, Jun 18, 2010.

  1. itwasepic macrumors newbie

    Apr 11, 2010

    I bought Fusion and ran Windows 7 in a VM - within a few minutes my MBP (17" i7 4GB RAM) was wayyyyy hot (left side bottom/top). I mean, I am a little concerned with how hot it gets. I'll look into smcFancontrol but want to know if upgrading to 8GB RAM will do the trick as well?
  2. Matthew Yohe macrumors 68020

    Oct 12, 2006
    Please don't look into smcFanControl. The Mac will control heat as it needs to and doesn't need help. If it breaks because of heat, Apple will gladly replace it.

    Increasing RAM shouldn't help much.

    Check Activity Monitor, check how much CPU is being used by the fusion process. Did you set up Fusion to use multiple cores? It would make sense to distribute operations over multiple cores.
  3. itwasepic thread starter macrumors newbie

    Apr 11, 2010
    I adjusted it to spread across 4 CPUs and 2GB RAM. Hopefully this will lower the heat.
  4. runebinder macrumors 6502a


    Apr 2, 2009
    Nottingham, UK
    I prefer to use SMC fan control, especially if I'm going to be playing a game in Steam. Someone made a good point that what causes issues with electronics is due to the expansion and shrinking caused to changes in temps, so if you can keep the heat from going too high in the first place it's better in the long run. Cheaper to have to replace fans than a logic board.
  5. Frosties macrumors 6502a


    Jun 12, 2009
    The i7 have only 2 physical cores, wmware recommends to set the cpu to half the number of cores. You could test with 2 but 4 would not be recommended for your setup.

  6. alphaod macrumors Core


    Feb 9, 2008
    Increasing RAM will only help make the VM faster by letting you allocate more RAM to the VM. And this increase is only evident if you are running things in your VM that needs the increase in RAM.

    It won't make it run cooler.
  7. dyn macrumors 68030

    Aug 8, 2009
    That implies you added 4 virtual cpu's to the vm. In order to do so you need to have 8 physical cpu's/cores in your machine. The MacBook Pro only has 2 so the max number of virtual cpu's you can use in a vm is 1. If you add more this will slow down the vm and your Mac to a state where you can't use it anymore. It will also eat up the cpu in the MacBook Pro causing it to generate an awful lot of heat.

    Please read the instructions in Fusion before you do something like this. The instructions clearly tell you NOT to do this. It will do the exact opposite and cause the MBP to heat up even more. The following document should help you out in setting up the vm properly: Choosing the Right Virtual Machine Settings.

    You should really check out the cpu usage of the vmware-vmx process in activity monitor. If you're doing things like installing a lot of updates it is quite common to reach 100% cpu usage (mind you, you can go up to 200% cpu usage; the 100% simply means you're using 1 of the 2 physical cores). Running at 100% cpu usage for that single process would also mean that the cpu gets a bit hot (but that is what you'd expect). Adding more memory will not slowdown the cpu usage in anyway and thus won't have any impact on the cpu heat.

    What are the temperature readings from your MacBook Pro (you can use something like iStat Pro to figure that out)?
  8. gwsat macrumors 68000


    Apr 12, 2008
    I agree. Last February I upgraded my MBP's RAM from 2Gb to 6Gb (the maximum amount of RAM this model of MBP can reliably accommodate). Although Fusion and the Windows apps I generally run under it run much faster and more stably with 6Gb of RAM than they did with only 2Gb of RAM, the heat output has remained about the same.
  9. Inside_line macrumors regular

    Jun 21, 2005
    If anything, the heat goes up. More RAM = CPU fed more often, worked harder. RAM also gets very hot.
  10. xi mezmerize ix macrumors 6502a

    xi mezmerize ix

    May 24, 2010
    Maryland, USA
    The mbp is made of aluminum...its gonna feel a lot hotter than another notebook thats made out of plastic. Don't worry about it.
  11. CSHawkeye81 macrumors member

    Jun 30, 2009
    Arlington VA
    Trust me I have the same issue when running VMWare on my mbp and adding more ram will not change the heat issues. Just for some reason VMWare fusion and Parallels on the new i Series CPU's tend to tax them more.
  12. Azathoth macrumors 6502a

    Sep 16, 2009
    VMWare will turn on the 330m - use GfxCardStatus to keep it on intel only if you dont need the graphics power.

    I went over to VirtualBox to run Win7 (set to 1 CPU, 768MB) on my 4GB i5 MBP15. Just running msn on Win7 and the CPU temp is <50deg.
  13. dyn macrumors 68030

    Aug 8, 2009
    It's not Fusion that triggers it, it's MacOS X. Parallels will have the same issue and I think VirtualBox as well. They all use things like OpenGL which has been listed as one of the items that will make OS X trigger the Nvidia GPU. With GfxCardStatus you can enforce the Intel GPU but this can be buggy at times since not everything seems to like it. Running a Windows vm in Fusion on the Intel GPU will cause a BSOD in the vm. Using something like FreeBSD without any GUI works perfectly fine on both GPU's

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