If your new computer came with UEFI instead of the legacy BIOS, you are able to get a significantly faster boot time of your Windows OS. UEFI is designed to initialize the hardware faster and then delegate the boot process to the OS. To enjoy the benefits of UEFI, you need to install Windows correctly in UEFI mode. Here is what you need to do for Windows 10.
Many modern PCs run the installed OS in UEFI mode. But almost all of them have a fallback mode which allows the hardware to be configured in the legacy mode called 'BIOS' mode. Here is how you can tell which mode exactly is used on your Windows 8.1 PC.