Been spending a great deal of time trying to find thrash metal that fits this description. I mean like Thrash metal that's fast, heavy as shit, catchy as hell and never lets up on the intensity. So far the only bands I have found that brings this to the table is Switchtense, Hammercult, Austrian Death Machine, and Toxic Holocaust's later work. http://www.youtube.com/watch?v=iu-_Dx7GJsk Here's a link of an example. Can anyone recommend me some bands to help me finish this thrashy journey?

Demolition Hammer is fast but has a lot of crushing heavier parts usually in the chorus.

http://www.youtube.com/watch?v=x_7-dxSOQ8Q

Don't let the tempo of the song lead you to believe everything they do is mid-paced!

morbid saint too obvious?

also check out nocturnal breed and lost society

How about Carnal forge's Firedemon, its pretty intense.

http://www.youtube.com/watch?v=GNpdjph325w
http://www.youtube.com/watch?v=_VwW9FfmUP0

What about Violator? also Tungsteno and Carneross, both from Argentina. Another band with non stoping badassery and evil as fuck
is Nekromantheon, maybe the epitome of relentless thrash metal. They are from Norway and Fenriz like 'em so go check it out.