I noticed a massive increase like Steven, Bob.
My Virtual Machine takes only a few seconds to boot up. Non-SSD, 32GB of HDD Space + 4GB of RAM... Windows 8.1 for me took the same time on an SSD (32GB) w/ 16GB's of RAM.
Main difference being, 8.1 (My first OS) took the same time too boot on my SSD, and 4times as much ram as Windows 10 does on VirtualBox.
I will be Dual Booting my system within the next 8 hours. I already have EUFI and all that jazz. It'll be interesting to see whether or not my system will co-operate. I've not received conformation that Windows 10, my BIOS and GPU will support Win 10. If not, well, Intel Adapter is what I'll be using -_-