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I am looking at this system below with ensuring we have enough memory to carry out day to day tasks, we have been hitting a bottleneck recently because there was only a 2GB page file, I've changed that to the recommended 1.5 times the physical ram and it looks ok. However CPU usage has spiked as below, is this down to the increase in I/O, the PF usage seems to be ok so far would this server degrade once physical RAM limit is reached.

PF USAGE

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would this server degrade once physical RAM limit is reached.

Yes, the performance of the server will degrade once it runs out of RAM.

The recommended size of your page file is not simply a multiple (1.0x, 1.5x, 2.0x, etc.) of your physical RAM. (That is 1990s era advice that is not accurate. Even Microsoft once published such bogus advice, but it is not accurate.)

The recommended size of your page file is just enough so that your Peak Commit Charge never exceeds your RAM + Paging Files (plus a little buffer.)

In a system that is low on physical RAM, the page file on the disk gets used heavily, and the disk is much slower than RAM. So you experience degraded performance.

Your current commit charge is ~48GB, but has peaked up to ~66GB at some point. You need to make sure that you have enough physical RAM + Page files to keep that covered.

It doesn't hurt if your page file(s) is/are too big, other than that it wastes disk space. What matters is how heavily the page file is used. If your page file is too heavily used, then get more RAM, or put your page files on faster storage.

We don't really have enough information in this one screenshot to diagnose your CPU usage. But I can tell you that increasing the size of your page file should not have any significant negative impact on CPU usage.

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