On 2007-10-22, General Schvantzkopf <schvantzkopf@yahoo.com> wrote: > On Sun, 21 Oct 2007 15:18:11 -0700, pgega wrote: > >> I meet the opinion that I should use amd64 architecture instead of x86. >> Because x66 can handle up to 4GiB of RAM, but some of it will be >> allocated to hardware, is it right ? > I have a AMD64x2 system, using a none-SMP kernel, 1 Gig of memory shows up, using a SMP kernal, 2.5gigs show up. (2.5 gigs installed) -- greymaus Just Another Grumpy Old Man

General Schvantzkopf <schvantzkopf@yahoo.com> writes: > >> I thought that the 1G only mode was slightly more efficient - assuming >> that you only have 1G of memory. Then again, I could be completely >> wrong. ;-) > >The page tables are probably smaller but that hardly matters. IIRC the main difference is that the 1G kernel can map the physical memory and the current process's virtual memory (up to 3GB) into its address space at the same time, and therefore requires fewer page table operations, TLB flushes and such. Of course, if you run a 64-bit kernel, you get the same advantage for any amount of RAM that you can currently put into a machine. - anton -- M. Anton Ertl Some things have to be seen to be believed anton@mips.complang.tuwien.ac.at Most things have to be believed to be seen http://www.complang.tuwien.ac.at/anton/home.html