Lock Pages In Memory

I was doing some benchmarks with Sandra & noticed in Windows 7 that my memory bandwidth was reduced from XP & Vista...but why?

So I looked all the way at the bottom of the bench to see a exclamation with a warning. So I double clicked it & it brought this up.

" Warning W5010 : Cannot use large page memory pages due to lack of privileges.

Fix: Use the Local Security Policy to give yourself lock memory pages privilege.

Large memory pages greatly improve performance when large memory blocks are allocated."

So I gave myself privileges to enable this and was very surprise with the performance increase although I still don't understand what it did & why so much of a memory bandwidth increase...

Screen-shots below say it all... from 62% (6497mbs) memory bandwidth efficiency to 65% (6838mbs) with lock pages in memory enabled.

Does anyone here know what this does exactly & can you explain it to me to where I understand if this is a setting that is good or bad to have on for system performance.

btw, I have 4Gbs of installed memory on Windows 7 32bit.