On Wed, Oct 28, 2009, Alan Tyree wrote: > That's interesting, Daniel. So what are my tradeoffs. Run the normal kernel: > faster but only 2.5gb; Run the bigmem kernel and suffer the performance but > have more memory.
Hm, does Linux actually -copy- data around when doing PAE? The whole point behind PAE is to give you a larger amount of address space usable by concurrent processes. So each process will have a differently mapped set of "PAE" RAM pages as needed, along with the shared kernel stuff. I know that FreeBSD will do some data copying to and from devices that are not "PAE aware" (ie, hardware that only addresses up to 4gig of memory space, and drivers which haven't been converted over) but for individual processes it isn't all that bad. > Aside from the work mentioned above, I also edit some really big video files > and do ffmpeg transformations on them. Right. In which case 64 bit is for you. > So, is there some way of choosing which of the above is the best option for > me? I'd suggest trying both out and see. Typically for things like graphics/video editing, I suggest 64 bit almost exclusively now because the programs are written assuming they can hold a lot of data in RAM. Adrian (Who isn't Daniel, but has hacked on a bit of PAE code in his time.) -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
