Mutant pagefile (it jumped to a different partition all by itself)

Hello guys.

I am running w10 x84 10586.63

Two days ago I have found out that pagefile.sys has automagically moved from c drive to d drive and it is 8GB in size now (amount of physical ram).

Anyway, what I want to know is why the pagefile was moved to a different partition.

My hard disk just has got two partitions (MBR style)

C: System drive, 50 GB -> 23,2 GB free
D: Data drive 425 GB -> 223 GB free

I have double checked and pagefile is still set to "auto-manage by Windows".

Any ideas?

For best performance the pagefile should be on the most active partition (because that is where the heads will be most of the time) of the least active physical disk (to minimize competition with other disk access). With only one drive it should be on the same partition as the OS. But with only a 50 GB system partition that could be a problem.

Post a screenshot of the pagefile configuration dialog.

eLPuSHeR said:

Anyway, what I want to know is why the pagefile was moved to a different partition.

What kind of "why" is this? Why is it allowed? Or why did Windows decide to do that?

As for "why it is allowed"... By default all your drives are set up for "System managed" page file. Which means that there's nothing unusual in additional pagefiles appearing on any of your drives or one pagefile jumping from drive to drive. If you want to prevent this from happening you have to go to advanced system settings and manually configure your drives for pagefile.

As for "why Windows decided to do that"... Apparently Windows came to conclusion that relocating the file will improve paging performance. There's no way to say anything specific without knowing more of your setup. Is C: and D: the same physical drive or not?

LMiller7 said:

For best performance the pagefile should be on the most active partition (because that is where the heads will be most of the time) of the least active physical disk (to minimize competition with other disk access). With only one drive it should be on the same partition as the OS. But with only a 50 GB system partition that could be a problem.

Post a screenshot of the pagefile configuration dialog.

Here:

LMiller7 said:

For best performance the pagefile should be on the most active partition (because that is where the heads will be most of the time) of the least active physical disk (to minimize competition with other disk access). With only one drive it should be on the same partition as the OS. But with only a 50 GB system partition that could be a problem.

Post a screenshot of the pagefile configuration dialog.

This is only partly true if you have multiple drives on one physical drive and if an hdd, and even then not always true depending on how congested drive is as pagefile could get badly fragmented.

If drives are physically separate it is better to have multiple pagefiles.

Either way, it is best to let windows choose.

For SSDs it does not matter if in same or separate partition, although it is considered by some pagefile should not even be on ssd to minimise number of write cycles.

cereberus said:

although it is considered by some pagefile should not even be on ssd to minimise number of write cycles.

At the same time, it is considered by some that the primary purpose of SSD is to host the page file and thus improve swapping performance. For which reason a good system setup would marry these two viewpoints by relying on two physically separate SSDs: one for system, programs and other non-changing data and another one for page files, search indexes and various volatile caches.

I disabled "let Windows manage all drives automatically" and forced the pagefile on C (fastest partitition). Flushed prefetch folder and the pagefile returned to its normal recommended size (1,8 GB). Now it's 8GB again. This is driving me crazy. Maybe I have a memory leak somewhere. According to task manager everything seems fine though.



I think I am not bothering anymore. I have enough free space to accomodate an 8GB pagefile.