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http://www.anandtech.com/show/6873/nvidias-geforce-700m-family-full-details-and-specs/2
They're mostly the same as GeForce 600M series cards, except that clock speeds may or may not be higher. For example, is "up to 900 MHz" really higher than "up to 800 MHz"? Maybe. It depends on how the laptop vendor feels like clocking it.
There are some new cards there that have two Kepler SMXes, but only one memory channel, and DDR3 at that. If two channels of DDR3 was throttling performance way back, then what happens if you only have one channel of DDR3 memory? That's not going to end well if you had ideas about playing games on it.
The basic rules for the GeForce 700M series cards are the same as for the 600M series cards: if it doesn't have at least a 128-bit GDDR5 memory bus, you don't want it. The new single memory channel cards in particular will typically get crushed by AMD integrated graphics, and may exist only as a way for Nvidia to get rid of defective dies other than by throwing them in the garbage.
Comments
Really the only significant change I could see was they updated to Boost 2.0. That alone could provide for the increase in maximum frequency (although it may or may not do anything for actual performance).
Even with that - meh. Bunch of rebadged low-mid range mobile cards with the new 700 series, just so they can say they launched a new series and try to squeeze more life out of mediocre products. Nothing exciting here.