Originally Posted by Core2uu
Okay, but what does "normal" standby list mean? As in, how is the data being cached on the unused portion of my RAM currently different from when I have SuperFetch enabled?
The stand by list has been around since initial incarnations of the Windows NT kernel. With SuperFetch enabled, it preemptively fetches data off the disk and into RAM, but it uses previous infrastructure to store it (i.e. SuperFetch data actually goes into the stand by list anyway).
Without SuperFetch, the stand by list is regions of memory that are associated with a process, but not in a process' working set (i.e. the memory manager has determined that other pages would better suit in the working set of the process, and thus moves some pages out to the stand by list). When the process requests those pages, a "soft" page fault occurs and the memory manager moves the page straight back into the working set of that process. Contrast this to a "hard" fault where the page is actually fetched from disk (either the application binary, the page file, or the location of a file on disk in the case of a memory mapped file).
When or if memory contention becomes high, the memory manager begins re-purposing the pages in the stand by list. In Windows NT 6.0 and higher (i.e. Vista and up), there are actually 8 stand by lists, each numbered by priority (zero to seven). The memory manager automatically determines priorities of stand by pages, and re-purposes memory from lowest priority lists first as required.
Note that "cached" is actually the sum of the pages in the stand by list plus the sum of the pages in the modified list. And because I'm on a roll here, I'll explain a little bit about what the modified page list. Basically the modified page list is a cache of pages that have been modified (i.e. the memory manager cannot discard the page and bring it back from disk because it has been modified by the process). So, when a page is removed from a process' working set that is determined to be modified it gets put on this list instead - this then lazily wakes up a system thread called the modified page writer. This thread writes the modified page to disk (page file, or file location if a memory mapped file) and then either forgets about it, or moves the page to the stand by list if available. Pages in the modified page list are not available for re-purposing like the stand by list, though. Eventually these pages get written to disk or moved to the stand by list (or both, but always written to disk).
And if you like diagrams, here's a great one that shows the flow of pages throughout the memory manager inside the Windows NT kernel: