Does a KVM switch REALLY disable the monitor?

Quick question..

I just bought a KVM switch to use with a secondary monitor which is shared between 2 PCs. My main display is HDMI (always plugged into main PC) and the secondary (used as an 'extension') which is attached to the KVM is obviously VGA. I have a laptop plugged into the KVM so I can switch between my PC and laptop. However, when I switch the KVM to the laptop, it brings the laptop's signal in just fine, however, my main PC still says there's a monitor displayed but it's considered a "Generic Non-PnP Monitor" with a resolution of 1024x768. I can also still move my mouse "over" to where the other monitor would be and it disappears, almost like it's still being rendered even though it isn't technically.

So my question: When the KVM is turned to the laptop, my main PC still says there's a monitor connected. Is my main PC still rendering those extra pixels?

The goal in getting this was to be able to easily disable the second monitor (for gaming) for performance's sake, and then re-enable it for office work.


***EDIT: I did an experiment and did a print screen and then viewed it in Paint... Well, it looks like those pixels (1024x768) from that 'disabled' monitor are in fact being rendered. Is there a way to completely DISABLE the monitor on my main PC when the KVM is switched to the laptop??

That is how KVM devices work. You generally don't use it for a secondary monitor and you wouldn't want Windows disabling your main monitor every time you switched away from it. The processing power required to "render" those extra pixels is effectively nothing compared to the full power of the computer.

I'm assuming the KVM is non-configurable, so there really isn't a way to resolve this other than completely unplugging the cable from the laptop, which would trigger the laptop to switch into a single monitor configuration.