Well the X1400 now has spec's up on Ati's page it's a 4 pipe card with 2 vertex engines, and 128 bit memory interface, it weighs in at 105 million transistors.http://www.atitech.com/products/mobi...400/specs.html
This would make it a variant of the X1300 mobility, which is also a 4 pipe 2 vertex card with 105 million transistors, most likely the only differences are clockspeeds and voltage.
For the Record the X700 mobility has 8 pipelines, and 6 vertex engines, and 128 bit memory interface.
Also for the record in 3dmark 2005 The Desktop X700 will return around 3600 points, compared to around 2800 points for the desktop X1300. And the X700 Desktop part will manage 16 FPS in FEAR @ 1024x768 Ultra details, compared to 12 FPS for the Desktop X1300 part. Obviously I have not seen benchmarks from the laptop X1300 and X1400 parts so I can only guess about performance based on the performance of their respective desktop parts, and based on the benchmarks I feel the X700 should be the faster part.
Believe what you want, Ati has said that the X1400 is a low power part for thin and light laptops. Ati has clearly positioned the X1600 mobility as a replacement for the X700 mobility, and the X1600 has more than 30 design wins meaning it will be showing up almost every where the X700 was before.
Anyways all of this is totaly geting off topic, The poster wanted to know about the best 15.4" gaming laptop, and that is Clearly going to be an X1600 mobility part, I would suggest the Acer 8200 series as I already have, and It's a 1.66 ghz for the 8202 vs 2.0 ghz for the 8204, There will be some difference but it should not be huge. In raw clockrate the 1.66 is 83% as fast, and since CPU scaling is not quite linear as you increase clock speeds I would say you might see 5~15% real world differences depending on what you are doing with the laptop.