Running the Task Manager should give you a utilization indication.
I believe only the active display page is processed.

... and if you only use one main monitoring page, you can delete the ones created automatically for each device too.
You can re-generate those in aquasuite settings should you have a need for them.
It's actually a good idea to create one single monitoring page, just to remove the clutter when you have several devices plugged in

I have several Overview Pages that I use. One for overall system stats, and another that is GPU based. I have versions of these pages with item coordinates set to place the pages on my 2 internal stat displays, which in the Windows raster are located far from coordinate [0,0]. If I want to look at these pages on my desktop, I have to scroll way over to get to them. To get around this, I made copies of these pages but with starting coordinate [0,0]. This way I can view the pages on my stat displays and also view them on my main display without having to scroll way over to see them. Works great. I also have a few test pages where I do my experiments with XAML code and graphs. I have not noticed that having all of these pages puts more load on the CPU.

I have noticed that having AQS running consistently adds about 10ns to my memory latency. I discovered this while overclocking my RAM. I could not figure out why I was getting ~70ns of latency in the AIDA64 Cache & Memory Benchmark when others with similar setups were getting ~55ns. By process of elimination I discovered that ~5ns was due to various things running in the background, but the big one was AQS. Terminating AQS and its service lowered latency by ~10ns. I did some Googling and discovered that others have also noticed this. I don't know why AQS adds 10ns of memory latency, or if it depends on how AQS is set up. I consider AQS to be a "critical" program (along with HWINFO), so I just live with the 10ns of additional latency.