said by BronsCon:
You're thinking spinning disk, where there are performance implications to fragmentation. Taking that out of the equation changes the game; the ideal pagefile is the smallest one you can get away with at any given moment.
Re-sizing is extra IO, though if you have enough ram then set a small page file, I have 24GB of ram so I set a tiny pagefile with same min/max size so its there but doesn't do anything.
If it has to change the file size that is more IO than if it just had to update the data of the file, so its still a good idea for a non-changing size. (though if you have enough memory to not need a pagefile then it's going to sit there empty and not have an effect anyway.)
and short of 2 programs I use nothing has come close to filing my ram and even those 2 haven't fully filled it.