Both quad-core CPUs use the 45 nm Clarksfield core of the Nehalem micro architecture, and were originally launched in June of 2010.
According to a product change notification, the processors have a last order date of November 9, 2012 and will ship until supplies are depleted. Both mobile CPUs use the Socket G1, are rated at 45 watts TDP and support DDR3-1333 memory. The 740QM runs at 1.73 GHz and the 840QM at 1.87 GHz.
To make room for Ivy Bridge, Intel had removed both processors some time ago from the official pricing sheet, which does not list any 45 nm notebook desktop and notebook processors anymore, aside from Atom chips and the Celeron T3500.