Using 64-bit Linux Software To Reduce Power Consumption?

[phoronix]

Phoronix: Using 64-bit Linux Software To Reduce Power Consumption?

With Ubuntu 16.04 LTS due for release next month, I found it time to do my occasional 32-bit vs. 64-bit Linux OS comparison for showcasing the performance difference of using the 64-bit software on supported hardware. This time around, at a premium member's request, I also did some power consumption monitoring between the 32-bit and 64-bit builds of Ubuntu 16.04 on an Intel laptop/ultrabook...

http://www.phoronix.com/scan.php?page=news_item&px=32-64-16.04-Power-Tests

[mmstick]

It would make sense that 64-bit software running on a 64-bit processor uses less energy than 32-bit software running on a 64-bit processor. Just as unused memory is wasted memory, unused registers is wasted registers.

[rob11311]

It would make sense that 64-bit software running on a 64-bit processor uses less energy than 32-bit software running on a 64-bit processor. Just as unused memory is wasted memory, unused registers is wasted registers.

With better ASLR in the 64bit virtual address space (in 32bit there's not actually many possibilities) I'm not sure of any real reasons to use 32bit on machines with >= 2GiB RAM.

[bvbfan]

Just use tlp

[rabcor]

Dat color variation thou! 8/10 couldn't tell which was 32 bit and which was 64 bit

[schmidtbag]

It would make sense that 64-bit software running on a 64-bit processor uses less energy than 32-bit software running on a 64-bit processor. Just as unused memory is wasted memory, unused registers is wasted registers.

With leaky transistors, yes, unused registers will waste power. But generally speaking, that would be a negligible power difference. The way I see it, running 64 bit saves power because the CPU is accomplishing more in less time, and depending on the task, can handle more complicated calculations without working as hard, and therefore runs more efficiently. That being said, in some cases, if you were to max out a 64 bit CPU 100%, I would bet that it would use more power than running the same task in 32 bit.


As for "unused memory is wasted memory", I really hate that quote, because that couldn't be further from the truth. It's statements like that why we end up with such bloated software.

[Kano]

If you want to use Google Chrome with Flash (Chromium still runs on 32 bit) then you can only use a 64 bit OS. Hard time for old netbooks, well they have been too slow for Flash videos anyway...

[doom_Oo7]

I would be interested in knowing the difference with x32. I think that Debian supports the arch.

[hajj_3]

maybe you could try this with an AMD apu too?

[Michael]

maybe you could try this with an AMD apu too?

I have no AMD APU laptops.