There are (at least) four Tensions.

1) Tension, a Taiwanese male asian group that sings hip hop, acappella, and so on. There are 5 people in Tension and they have raomed yesasia.com in asia and also many asain people. they may not be the one of the most top 100 people searched on the internet but they are one of the many 100 people asian groups people listen to. Another asian group that are more into rap, and stuff that Tension is like, is the Teriyaki Boyz
2) Tension, a club/vocal house project of late 80's/early 90's, who had a big club hit with their "It's a place called heaven".
3)Tension : heavy/power metal band from Baltimore(USA) formed in 1984 by Tom Gattis (Wardog/Ballistic) and released only one full-length album Breaking Point in 1986.
4) Tension are a four piece Melbourne based Australian technical/nu-metal band, sharing similarities with bands like Deftones, Meshuggah and Isis. They released a self titled EP in 2002, and an album "The Blind Leading the Deaf Following the Dumb" in 2005.
5) TENSION: PUNK ROCK. From Leamington Ontario, Canada. As far as I know they are active now still.
6) Tension: Punk/Pop from Rhinebeck, New York.