 "Octavarium" was the last album under their seven-album deal with Elektra Records, which had inherited the contract upon its absorption of EastWest Records.Dream Theater started the Octavarium Tour extensively throughout 2005 and 2006 to celebrate their 20th Anniversary as a band, including a headlining spot on Gigantour alongside Megadeth and put together by frontman Dave Mustaine, also featuring Fear Factory, Nevermore and Symphony X.During a show on August 2, 2005 in Dallas, the band paid tribute to Pantera's late guitarist Dimebag Darrell by performing the song "Cemetery Gates" as an encore.