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j*tech
January 6th, 2011, 09:39 AM
so my cpu is AMD Athlon 64 x2 dual core, but im unsure what version my kernel is ("about ubuntu" not working for me)....i ran "uname -a" (but kinda unsure how to correctly read it), and it came back "2.6.35-24-generic" and "i686"...."uname -p" comes back as "unknown".....

what bit is my system (is it 64 since my cpu is?) and my kernel?.....why is "about ubuntu" not working for me?....is it possible to run a 32 bit version of ubuntu on a 64 bit system?....

Runckle
January 6th, 2011, 09:45 AM
Use the 64 bit.:guitar:

walt.smith1960
January 6th, 2011, 10:19 AM
Yes, right now you're running 32 bit. "i686"=32 bit. If you have 3 GB or less RAM installed, I think there's some advantage to 64 bit but I'm not sure how much. A 32 bit operating system can use about 3.2 GB RAM without the use of PAE, a 64 bit operating system can use 128 GB. RAM. I think there are some performance advantages of 64 bit in addition to using more RAM when doing CPU intensive tasks. I run both 32 bit and 64 bit on different machines and don't see much speed difference either way but system monitor shows more RAM in use on a 64 bit system running the same applications.

amjjawad
January 6th, 2011, 10:21 AM
This thread doesn't belong here.

http://ubuntuforums.org/showthread.php?t=1486750

http://ubuntuforums.org/forumdisplay.php?f=302 << You'll find what you need here. Just use "Search" and you'll find many threads with exactly the same title.

cascade9
January 6th, 2011, 10:37 AM
A 32 bit operating system can use about 3.2 GB RAM without the use of PAE, a 64 bit operating system can use 128 GB. RAM. I think there are some performance advantages of 64 bit in addition to using more RAM when doing CPU intensive tasks. I run both 32 bit and 64 bit on different machines and don't see much speed difference either way but system monitor shows more RAM in use on a 64 bit system running the same applications.

64bit (AMD64/x86-64) goes much, much higher than 128GB....




Larger physical address space: The original implementation of the AMD64 architecture implemented 40-bit physical addresses and so could address up to 1 TB (240 bytes) of RAM.[1] (http://en.wikipedia.org/wiki/X86-64#cite_note-amd-24593-0)(p4) Current implementations of the AMD64 architecture (starting from AMD 10h microarchitecture (http://en.wikipedia.org/wiki/AMD_K10)) extend this to 48-bit physical addresses[9] (http://en.wikipedia.org/wiki/X86-64#cite_note-amd10h-8) and therefore can address up to 256 TB of RAM. The architecture permits extending this to 52 bits in the future[1] (http://en.wikipedia.org/wiki/X86-64#cite_note-amd-24593-0)(p24)[10] (http://en.wikipedia.org/wiki/X86-64#cite_note-9) (limited by the page table entry format);[1] (http://en.wikipedia.org/wiki/X86-64#cite_note-amd-24593-0)(p131) this would allow addressing of up to 4 PB (http://en.wikipedia.org/wiki/Petabyte) of RAM. For comparison, x86 (http://en.wikipedia.org/wiki/X86) processors are limited to 64 GB of RAM in Physical Address Extension (http://en.wikipedia.org/wiki/Physical_Address_Extension) (PAE) mode,[11] (http://en.wikipedia.org/wiki/X86-64#cite_note-shanley-ppro-10) or 4 GB of RAM without PAE mode.[1] (http://en.wikipedia.org/wiki/X86-64#cite_note-amd-24593-0)(p4)

http://en.wikipedia.org/wiki/X86-64

There is a big difference between 32bit and 64bit as far as heavy processing goes. Even on normal tasks, 64bit tends to be faster (probably in the order of 5-10%).

http://www.tuxradar.com/content/ubuntu-904-32-bit-vs-64-bit-benchmarks

http://www.phoronix.com/scan.php?page=article&item=ubuntu_32_pae&num=1

BTW, those are not exactly new tests, its more than possible that current 64bit would be faster in comparison to 32bit.

You might not notice much difference if you dont do very CPU heavy tasks, but you probably also wouldnt notice if somebody overclocked your machine to give it 5-10% more power (which is one reason why I think its onyl crazy people who buy $1000 CPUs that woudl be lucky to be 5% better than a $500 CPU, but thats a different story....)

walt.smith1960
January 6th, 2011, 10:54 AM
64bit (AMD64/x86-64) goes much, much higher than 128GB....


Yahoo! answers lied :rolleyes: :lol:. I don't know of any commonly available PC motherboard that will hold 128 GB, let alone 256 TB. Of course "real computers" that require their own rooms and air conditioning systems are quite another matter. And yes, Linux will run on those too which I find quite remarkable.

cascade9
January 6th, 2011, 11:05 AM
Yahoo! answers lied :rolleyes: :lol:. I don't know of any commonly available PC motherboard that will hold 128 GB, let alone 256 TB. Of course "real computers" that require their own rooms and air conditioning systems are quite another matter. And yes, Linux will run on those too which I find quite remarkable.

I wouldnt say 'lied', probably just outdated information. See this page-

http://www.redhat.com/rhel/compare/

RHEL ver 3.0 had a 128GB limit on x86-64. Its out to 2TB/64TB (supported/theoretical) with the current ver 6.