Looks like a good start, now someone needs to look up the 360's previous best 6th and 7th launches to give a rough estimate of the actual numbers.

http://www.eurogamer.net/articles/2011-09-26-uk-top-40-gears-3-reigns-supreme

UK Top 40: Gears 3 reigns supreme

By Tom Phillips

Xbox 360 exclusive Gears of War 3 has surged to the top of the UK charts. It's the biggest launch of the year so far.

Codemasters racer F1 2011 placed in second, with last week's number one Dead Island in third.

Supremacy MMA, last week's other retail launch, failed to make the top 40.

Gears 3 sold more copies this week than the previous launch weeks of Gears 1 and Gears 2 combined. It's the seventh best launch week for an Xbox 360 title and the 12th largest individual format launch ever.

Elsewhere in the top 10, Deus Ex: Human Revolution holds firm at five, just pipped by evergreen Zumba Fitness encamped in fourth. Driver: San Francisco is sixth.

Recent releases Space Marine and Resistance 3 fill seventh and eighth, while Lego Pirates and Rugby World Cup are ninth and tenth.

EDIT: Mods please lock this thread as UK top 40 thread will cover the same discussion.