Speed Metal

This is the way i see it.
Venom is to Gorgoroth as Speed Metal is to Thrash Metal.
It's my weird way of seeing it.
Speed metal had a more of rock sound and wasn't as heavy or as refined as thrash.
 
Agreed. Speed metal is just traditional heavy metal played faster. Thrash requires a very specific riffing style, i.e. the "thrash riff" with its palm muting, jagged rawness, and possible punk influence.

Power metal is speed metal with a distinct European, classical, or faux-operatic overtone. Add some thrash riffs, and it becomes power/thrash. Add more punk, more rawness, it becomes thrash. Helloween's Walls of Jericho was a speed metal album. Keeper of the Seven Keys Pt.1 was a power metal album. Helstar is power/thrash, as most American power metal bands tend to be.

More speed metal? Exciter, Accept, Judas Priest, Motorhead, early Agent Steel, early Overkill, Iron Maiden (also NWOBHM), etc.
 
Speed Metal is ambiguous and has not real unifying principles aside from the speed.