has put the new 15.6-inch Acer Aspire 5742G with Nvidia's GT 540M core through its paces with some interesting results.
The performance doesn't seem to be much better with 400M series parts. It is only marginally faster than its predecessors and it appears the 540M is merely a tuned up core. The GT 445M ends up a bit faster in some tests, so it appears that the GT 540M is the direct successor to the GT 435M.
However, despite an unimpressive performance gain, the 540M has an ace up its sleeve thanks to Nvidia's Optimus graphics switching technology. Optimus allows the new Aspire to power down the graphics core and squeeze out a bit more battery life. It also keeps the chassis cooler.
You can check out the review here