Can't really tell, sorry. I've heard developers talk about some 20-30% being realistic, which shouldn't be much if you have a couple of cores.
For me (GNU/Linux with OpenJDK as Java environment), it runs on an average of 5-25%, mostly it jumps between, say, 9 and 22%.

Alternatively, you can install it on a remote server; member Llama has posted a great article on how to do that: https://medium.com/@RealCryptoLlama/how-to-setup-a-qortal-node-on-a-digitalocean-vps-ab70d3be2484
This way, you won't have to deal with Windoze in relation to QORT... might be worth a shot.

Disclaimer: I don't know much about the remote desktop software used in this post, so can't really say much about it... but it should also be possible to get it to run without GUI