64bit Or 32bit, Again..

There is more to 64-bit implementations than just address space. There are additional internal registers that can speed things up greatly that the 64-bit version of the compiler has access to but the 32-bit version does not.

This is pretty fascinating to me.... I ve a pair of, actually 3 machines that I believe are 64 bit compatible and I am not running 64 bit on any of them.... First machine is this one, an Intel 975 with 2 GB RAM and the core duo quad.....dual boot SUSe 10.3/XP. Second is an Intel 945 motherboard with a P4 proc and 2 GB of RAM with 10.3 and XP dual boot. According to their webpage the Intel 945 is 64 bit compatible but I do not know whether the P4 is or not. The P4 for what its worth does hyperthread in XP and shows 2 cores running 10.3 Third is the laptop a Toshiba with a core duo and a gig of ram , came with Vista but after very little of that foolishness I nuked and paved the HD and put 10.2 on it. Was running 10.2 with Beryl but after a while of playing with the rotating cubes I formatted again and put 10.3 on there. From what I understand the laptop is 64 bit compatible as well... In any case I ve read about less and less problems with 64 and the associated plugins that go with it... Im more and more tempted to try 64 bit because I like messing around with the machines.......I am curious particularly on the 945 with the P4 what performance gains would be experienced. This machine is way fast as is the laptop...... any comments or suggestions would be deeply appreciated

Regards from Mexico

Carr

To find out if a machine can run x86_64, if you have Linux, do:

grep -w lm /proc/cpuinfo

If you get a line starting with flags: and lm is one of the flags, then the CPU is 64-bit ready.

To find out if a machine can run x86_64, if you have Linux, do:

grep -w lm /proc/cpuinfo

If you get a line starting with flags: and lm is one of the flags, then the CPU is 64-bit ready.
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Many thanks.... have not tested the laptop yet but both desktops have the lm flag so Im good to go. I am a little hesitant about trying 64 bit on the laptop because of possible wi fi problems.....

Thanks much for the info....

Regards
Carr

This is pretty fascinating to me.... I ve a pair of, actually 3 machines that I believe are 64 bit compatible and I am not running 64 bit on any of them.... First machine is this one, an Intel 975 with 2 GB RAM and the core duo quad.....dual boot SUSe 10.3/XP. Second is an Intel 945 motherboard with a P4 proc and 2 GB of RAM with 10.3 and XP dual boot. According to their webpage the Intel 945 is 64 bit compatible but I do not know whether the P4 is or not. The P4 for what its worth does hyperthread in XP and shows 2 cores running 10.3 Third is the laptop a Toshiba with a core duo and a gig of ram , came with Vista but after very little of that foolishness I nuked and paved the HD and put 10.2 on it. Was running 10.2 with Beryl but after a while of playing with the rotating cubes I formatted again and put 10.3 on there. From what I understand the laptop is 64 bit compatible as well... In any case I ve read about less and less problems with 64 and the associated plugins that go with it... Im more and more tempted to try 64 bit because I like messing around with the machines.......I am curious particularly on the 945 with the P4 what performance gains would be experienced. This machine is way fast as is the laptop...... any comments or suggestions would be deeply appreciated

Regards from Mexico

Carr
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I wouldn't expect a huge boost-- 3-6% depending on the app maybe, In the world of microprocessor design, getting an extra 3% out of your design is a reasonably big deal, but as an end user you probably won't notice it. Most compilers seem to target AMD's implementation of x86_64 (which is why amd chips get a bigger boost from 64bit), and to my knowledge intel has never set their compiler folks to the task at optimizing things for 64bit performance. I'd guess that if happened one would see upwards of 10% performance increase in some apps. Likely the only reason why it hasn't is because they enjoy a reasonable performance lead over AMD at the high end of things.

Interesting and thanks for the info..... sorry I didnt say thanks in a more timely fashion but I didnt get an e mail notification there had been another reply to the topic...

You are right I doubt I would see anything from the 945 motherboard with the P4. In reality its lightly loaded, only doing workhorse things like e mail and chat during the day so Ill probably leave things alone. It is tempting tho to install it just to see what its like....naaah...maybe next week. LOL

again thanks
Carr

Although a bit old, here is a good head to head of 32-bit vs 64-bit with intels and AMD's in linux.

http://www.linuxhardware.org/article.php?s...6/08/22/0415251

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This sounded like a Deja vue to me. Remember the old time when i80386 just came out when I bunch of idiots still wanted to run their i80386 with a Win3.1 while some of us were already running Linux 32-bit on the same platform?

Bit of confusion? You must mean the 486, because the 386 was introduced in 1986-87, the Linux kernel wasn't created until 1991-92 (It wasn't in a useable state as an OS until much later), and Windows 3.1 was 1992.

No, the 32-bit CPU has instructions that allow a virtual space > 4G, but you need a differently compiled kernel. In the past distros SUSE provided some kernels with names like 64GB or bigsmp. But nowadays with the stock kernel, yes, it's limited to 4GB. In fact the effective RAM available will be < 4G due to remapping of some RAM by the hardware above the 4G line.

The 64-bit CPU has a much larger memory space of course. Not 2^64 due to chip limitations, but much larger that most people care.
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I think that the maximum memory address space for Opteron / Athlon64 architecture is 2^40, a full terrabyte.

I have to shamefully admit I didn't even know my Intel Q6600 could run the 64bit openSUSE. I've installed it and hope to run some timing tests, comparing the 64 bit install with my normal 32 bit environment. I somehow get the feeling that the imperceptible speed boost isn't enough to overcome even a tiny bit of problem. But so far, I haven't had any problems.