Instead of two levels of page tables to navigate through, you have three. So effectively looking up where something is stored in memory is 50% longer for that phase. That said, looking up where something is in RAM is very fast. Most machines are bottlenecked somewhere else (e.g. waiting for user input, or disk I/O or similar).
Cheers Ken -----Original Message----- From: Matthew W. Ross [mailto:[email protected]] Sent: Saturday, 4 April 2009 5:55 AM To: NT System Admin Issues Subject: Re: View PAE setting on W2K8 Isn't PAE a non-trivial memory performance hit? Or perhaps it used to be non-trivial, but newer memory technologies are fast enough to make it trivial today? --Matt Ross Ephrata School District ----- Original Message ----- From: Ben Scott Subject: Re: View PAE setting on W2K8 > On Fri, Apr 3, 2009 at 1:51 PM, Juned Shaikh <[email protected]> wrote: > > but I am wondering that why would you need to have PAE in win2k8? becuase > > you have 32 bit installation or you need this on Win2k8-64 Bit for 32 bit > enabled > > applications? > > PAE will let some versions of 32-bit Windows use more than 4 GiB of > RAM. Individual processes are still limited to 2 GiB of userland > address space (or 3 GiB with 4GT), but the system as a whole can use > that much RAM. You could, for example, have several processes, each > using 2 GiB. > > PAE is also needed to get the NX bit (No Execute, i.e., what > Microsoft calls Data Execution Protection). So even 32-bit XP and > Vista enable PAE for DEP. They just ignore memory above 4 GiB. Same > for 2003 Server Standard. ~ Finally, powerful endpoint security that ISN'T a resource hog! ~ ~ <http://www.sunbeltsoftware.com/Business/VIPRE-Enterprise/> ~
