The way of to get decreasing base CPU overhead

I faced the time I have to launch multiple UE client on single PC. ( Off course, the pc has enough GPU resource.)

But, at Launching multiple UE client, CPU usage hit the 100%.
Because single UE Client CPU usage is 15 - 20 % even if the UE project have not any changes since the new project create.
I used the client after package and no launching UE editor.

I wonder the UE packaged client has CPU overhead.
15 - 20% ( Intel(R) Core™ i7-10750H CPU @ 2.60GHz (12 CPUs), ~2.6GHz )

Any idea to decrease this cpu overhead?

I tried the setting of Quality, Target device( Desktop / Mobile), etc.

My PC envrironment

Operating System: Windows 10 Home 64-bit (10.0, Build 19041) (19041.vb_release.191206-1406)
BIOS: 1.4.0 (type: UEFI)
Processor: Intel(R) Core™ i7-10750H CPU @ 2.60GHz (12 CPUs), ~2.6GHz
Memory: 16384MB RAM
Available OS Memory: 16146MB RAM
Page File: 12675MB used, 20263MB available
Card name: NVIDIA GeForce RTX 2070

Im not sure if you should be launching multiple UE clients.