If I turn off my paging file, I’ve heard that in most cases, it will actually
slow down the computer rather than speed it up as it would logically seem to
because of the way that memory is managed. Could you shed some light on
that?
Windows memory management is complex, confusing, and the stuff of nightmares.
And that’s for the people who “understand” it. 
In this audio segment from an Ask Leo! webinar,
I’ll discuss paging files and virtual memory and why I don’t see how not having
a paging file could slow you down.
Become a Patron of Ask Leo! and go ad-free!
Transcript
If I turn off my paging file, I’ve heard that in most cases, it will
actually slow down the computer rather than speed it up as it would logically
seem to because of the way that memory is managed. Could you shed some light on
that?
This has in no way been my experience. The machine that I’m running right
now that’s hosting the virtual machine that you are looking at, has eight GB of RAM
and I have no paging file and I have not noticed any issues.
I honestly cannot think of a memory management scenario where not having a
paging file would slow you down. Clearly, whatever you end up writing to the
paging file takes more time that it would to read or write it from RAM so I’m
not sure what the details are.
Memory management is one of those things I’ve referred to as causing
nightmares even to the people that understand how it works because it is that
insanely complex. So I’m certainly not going to say absolutely not. But right
now, I’m with you. I don’t see how that could cause a problem or performance
impact.
Sorry, but what’s a paging file?
A paging file is your virtual memory. In fact, there are several different
files on virtual memory. So a paging file, I think, is one of three or four different
synonyms that all boil down to a file on disc that Windows uses kind of as
‘fake’ memory when it runs out of real memory.
So one of the things Windows can do, like I said I have eight GB of RAM on my
machine. If the combination of programs I’m running, for whatever reason,
require more than eight GB, Windows will start using the hard disc, this paging
file on the hard disc to copy out some RAM, some real RAM to make it available
for me. And then when the program that originally wanted what was in that RAM
to begin with, needs it, then maybe the memory that I just requested will get
written to hard disc and then the memory that the other program wanted gets
read back to real RAM and it gets used for awhile.
I’ll reference my earlier statement about memory management being insanely
complicated. Virtual memory and paging files are indeed part of that
complexity. Windows goes through a tremendous amount of effort to try and
maximize the performance of the machine given all of the different programs
that are running; priorities that they may have and options that it may have
available to it like the paging file.
So, basically, I’d refer you to this article ‘What is Virtual Memory?’ for an
overview of what it really means to be a paging file with the understanding
that a paging file is really just a synonym for virtual memory.
I can think of a couple things where not having a page file would slow you down.
If the file is not needed, no difference.
If the file is needed it is because the program cannot load code that is needed or needs more data space.
If that space is needed and there is not page file the program can do two things: shut down or do its own version of a page file.
Shutting down (or asking you to shut something else down to make room) will deffinately slow things down.
If the program needs to do its own version of a page file, they are not as intimately connected to the operating system as the one that comes with the operating system. I suspect that they can only swap parts of the memory that they were using instead of using memory that some program that is not active at the time is using. That would most likely require more swaps and slow things down.
A warning: Some program, like certain versions of Photoshop, will not run if you have no pagefile. Many defragmenting tools will not run with no pagefile.
My recommendation is to set the pagefile to start very small (say 100 MB) and grow up to a slightly larger number (say 1024 MB). The old wisdom of setting you pagefile to 1.5 or 2 times the physical memory is certainly no longer true if you have 8 GB of memory.
I agree with the 1st two comments. Swap and Page files are to computer RAM, as a microscope is to our eyes. They make things look bigger than they are. This was totally necessary in the days when RAM was very expensive, relative to disk storage. No so much today. However, if you do run a huge program like Photoshop and open several multi-mega pixel photos, or try to open a massive multi-tab Excel spreadsheet, and do not have a Page file, your system will return a nasty error, or go into a deadlock (freeze) depending on the circumstance.