I've bought a Lenovo Thinkpad Edge E540 and am intending to replace the pre-installed Windows 8.1 with Ubuntu. Will I be able to make use of processor technologies, such as Hyperthreading, VT-x etc., with a Ubuntu OS or will a replacement? I'm new to Linux so I'm apologizing in advance if there are any redundancies or false understanding in my question :)
Linux should support hyperthreading and virtualization (in probably all mainstream AMD/Intel processors):
Hyperhtreading - it working should show twice the amount of CPUs in system monitor, to check in more detail this post may help
You should be able to test to some extent whether these features work on your machine in the Live environment on the Install disc, so you don't have to install to see if it works. You hardware should be supported anyway.
Note their are varying drivers available for hardware (e.g. some CPU drivers support 'governors' that allow changing the frequency to increase speed or decrease power usage - this can easily be changed with this panel indicator).
Also, you can dual boot with windows 8 if you want, instructions to help with this are here.