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64bit Kernel running significantly cooler??

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wickedny5

macrumors member
Original poster
Jan 28, 2010
36
0
I have noticed my 15" macbook pro i7 mid '10 running wayyy much cooler than running the default 32bit kernel. I have iStat pro and the temperatures are all down by 15 to 20 degrees celsius and are steady. So why is that? What are other true benefits from running the 64bit? Only problem im having is connecting my blackberry for backups, RIM hasn't released any 64bit drivers so I guess ill have to be switching back and forth whenever i need to do backups and some tethering.
Some other things i've noticed is that Safari isn't eating my RAM away. It would eat up 1GB of RAM on the 32bit kernel, now on 64bit it fluctuates between 150-300.

System: 15" MacBook Pro i7 2.66Ghz, 8GB RAM, 500GB HDD @7200RPM, Anti-Glare Screen; Mid 2010
 
wickedny5 said:
I have noticed my 15" macbook pro i7 mid '10 running wayyy much cooler than running the default 32bit kernel. I have iStat pro and the temperatures are all down by 15 to 20 degrees celsius and are steady. So why is that? What are other true benefits from running the 64bit? Only problem im having is connecting my blackberry for backups, RIM hasn't released any 64bit drivers so I guess ill have to be switching back and forth whenever i need to do backups and some tethering.
Some other things i've noticed is that Safari isn't eating my RAM away. It would eat up 1GB of RAM on the 32bit kernel, now on 64bit it fluctuates between 150-300.
Click to expand...
If you have 4GB of RAM or more, you will instantly see noticable improvement in speed. It's not really needed to boot with 64-bit kernel if you don't have enough ram. I haven't noticed any temperature increase in my mbp i7 after activating 64-bit kernel on boot.
 
milan03 said:
If you have 4GB of RAM or more, you will instantly see noticable improvement in speed. It's not really needed to boot with 64-bit kernel if you don't have enough ram. I haven't noticed any temperature increase in my mbp i7 after activating 64-bit kernel on boot.
Click to expand...

I'm currently testing this on my Penryn non-unibody MBP, out of curiosity.
 
wickedny5 said:
I have noticed my 15" macbook pro i7 mid '10 running wayyy much cooler than running the default 32bit kernel. I have iStat pro and the temperatures are all down by 15 to 20 degrees celsius and are steady. So why is that? What are other true benefits from running the 64bit? Only problem im having is connecting my blackberry for backups, RIM hasn't released any 64bit drivers so I guess ill have to be switching back and forth whenever i need to do backups and some tethering.
Some other things i've noticed is that Safari isn't eating my RAM away. It would eat up 1GB of RAM on the 32bit kernel, now on 64bit it fluctuates between 150-300.
Click to expand...

What program are you using to measure your temperatures? Maybe the program is wrong...
 
milan03 said:
If you have 4GB of RAM or more, you will instantly see noticable improvement in speed.
Click to expand...

I highly question that.
I tested the 64bit kernel on my Mac Pro and didn't notice ANY performance improvements whatsoever, yet has it anything to do with 4GB of RAM.

And that's exactly what most people say about 32 vs 64bit kernel.
It is unquestionable that there is a difference in some pro applications though.
 
My experience especially working with Logic Studio 64-bit tells me that with 64-bit kernel and more ram I can run not only more tracks, but more efficient.
Of course it depends on what you're gonna be using your mac for, but I can't see a single downfall in using 64-bit kernel so far. :apple:
 
milan03 said:
My experience especially working with Logic Studio 64-bit tells me that with 64-bit kernel and more ram I can run not only more tracks, but more efficient.
Of course it depends on what you're gonna be using your mac for, but I can't see a single downfall in using 64-bit kernel so far. :apple:
Click to expand...

If you're hardware and software is fully compatible with the 64bit kernel there is no disadvantage, that's right.

I'm not saying that the 64bit kernel isn't the way to go, just saying that most people won't see any difference in performance compared to the standard 32bit kernel, regardless how much RAM they use (which is 8GB max in the MBP anyway, 64bit kernel is only mandatory for more than 32GB of RAM, so MP only).
 
milan03 said:
If you have 4GB of RAM or more, you will instantly see noticable improvement in speed. It's not really needed to boot with 64-bit kernel if you don't have enough ram. I haven't noticed any temperature increase in my mbp i7 after activating 64-bit kernel on boot.
Click to expand...

I have 8GB of RAM, But the shocker to me is really the temperature difference. Its not only looking at the temperatures from iStat, but also feeling the macbook pro on my lap.. It feels obviously cooler than before. I use to need a book or magazine because it would get so hot running the 32bit kernel, now it just gets a little warm.. nothing uncomfortable
 
Could be because your computer is now using your HDD less for Page in/Out or Swap since it addresses the whole 8GB available.
Not sure...
 
milan03 said:
Could be because your computer is now using your HDD less for Page in/Out or Swap since it addresses the whole 8GB available.
Not sure...
Click to expand...

I think you hit the jackpot, I just noticed my Swap is at: 0/64MB and Page in: 45,788 Page Out: 0. When I use the 32bit kernel those numbers would be really High. Also I do have a 7200 RPM drive so im assuming they run hotter than the 5200 RPM. For those of you that run the 32bit kernel and say they can't notice a heat difference, do you use a 5200 RPM Drive??
 
wickedny5 said:
I think you hit the jackpot, I just noticed my Swap is at: 0/64MB and Page in: 45,788 Page Out: 0. When I use the 32bit kernel those numbers would be really High. Also I do have a 7200 RPM drive so im assuming they run hotter than the 5200 RPM. For those of you that run the 32bit kernel and say they can't notice a heat difference, do you use a 5200 RPM Drive??
Click to expand...


Your swapfile is that small and your pageouts are nonexistent because you just rebooted.

Mac OS X could always address more than 4 GBytes of RAM, whether 32 oder 64Bit kernel was used.
 
treichert said:
Your swapfile is that small and your pageouts are nonexistent because you just rebooted.

Mac OS X could always address more than 4 GBytes of RAM, whether 32 oder 64Bit kernel was used.
Click to expand...

I believe 64bit kernel can address more than 16 terabytes of RAM, whereas 32bit kernel can "only" recognize 16TB max. :D
 
32 vs 64 bit doesn't do anything to the temps. I have an early '08 2.4 MBP running in 64, the temps are exactly the same as they were in 32.
 
toxic said:
32 vs 64 bit doesn't do anything to the temps. I have an early '08 2.4 MBP running in 64, the temps are exactly the same as they were in 32.
Click to expand...

Oddly enough I with th OP on this even though I have 4GB of RAM and a SSD
Can't boast the same drop but I do notice a difference of about 5-10 degrees
 
toxic said:
32 vs 64 bit doesn't do anything to the temps. I have an early '08 2.4 MBP running in 64, the temps are exactly the same as they were in 32.
Click to expand...

Your absolutely right, It may not run hot on your macbook pro because its only effecting the mid 10' MBP's i5/i7. This has been a known issue among the community and there are many websites with the same complaints. Here are a few:

http://forums.appleinsider.com/showthread.php?p=1665016
http://www.engadget.com/2010/04/26/core-i7-equipped-macbook-pro- hits-100-degrees-celsius-your-lap/
http://www.tuaw.com/2010/04/26/report-core-i7-macbook-pros-running-hot/
http://www.product-reviews.net/2010/04/27/new-macbook-pro-core-i7-models-seriously-overheating/
 
Geekbench 32 vs 64 bit

I have the same rig as the OP, with a 7200 rpm dirve. Booted into the 64-bit kernel, I ran Geekbench 64 bit and Geekbench 32 bit, one right after the other:

32 bit: 5657
64 bit: 6254​

I ain't saying Geekbench is right, that 64 bit is faster, I am just reportin' the facts of what Geekbench says. If you don't like it, flame Geekbench, not me. :cool:
 
frankieboy said:
I have the same rig as the OP, with a 7200 rpm dirve. Booted into the 64-bit kernel, I ran Geekbench 64 bit and Geekbench 32 bit, one right after the other:

32 bit: 5657
64 bit: 6254​

I ain't saying Geekbench is right, that 64 bit is faster, I am just reportin' the facts of what Geekbench says. If you don't like it, flame Geekbench, not me. :cool:
Click to expand...

You can run these with the 32bit kernel and 64bit kernel without any real differences though. 64bit mode with the 32bit kernel still gets the performance gains.
 
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