M17x r2 or m15x

ok so i had an order for the r3 but cancelled it cause i didnt feel like waiting around to see what dell or intel was going to do and how long it was going to take. so i am trying to make a decision between these two. so some input would be great. i have put together a cart with both laptops. for the m17x r2 i choose the 720 processor since i was reading it isnt that much of an upgrade to the 840. i put 4gb of ram cause i can upgrade that myself and i put duel 5870s. high rez screen and upgraded wireless. it came out to about $2500 with tax.

for the m15x i put the 840 processor it started at 6gb ram 1.5gb 460 graphics upgraded wireless high rez screen bigger battery and it came out to about $2300 ish.

so i will bring these thing to school and stuff. carrying it around isnt too much of a deal since i already have a 17 inch hp i carry. i the the r2 is alittle bigger than mine but not too much. i wont be playing crisis but i want to play my other games on highest settings without it lagging. games like mx vs atv reflex, test drive unlimited 2, cod mwf2, sims, and this laptop will be used for CAD for school since i am an engineering student so that extra screen space might be nice. but is it nice enough to carry around the extra size of the laptop and weight. let me know of specs i should consider and some opinions you guys have. having a difficult time deciding. also what is the battery life like on the m17x vs the m15x with the bigger battery on the m15x.

 

i would get the m17x, there is no point in getting the m15x with 840 since you already said that isn't much improvement for gaming. If you bought the m17x r3, im sure you wanted it for gaming. The m17x with crossfire is more suitable for gaming than the m15x. I can play any game out there(except for crysis and metro 2033) on max settings with no lag. Plus you can get 8gb of ram for like $70 online. i got my 8gb for $63 shipped. Just get the m17x with 740qm, rgb screen and 5870 crossfire, you will be happy with it.

 

I found out the hard way that the 400 series nvidia cards have been purposely gimped in professional applications using both d3d and opengl. GTX 460M performs at roughly 20%-25% of a GTX 285M in all Autodesk programs.

400 series openGL performance is so bad that it is not even possible to play minecraft (or whatever it's called) - an openGL game that can run on my core2 duo with integrated graphics.
Another comparison:
d3d dx9.0 + gtx 460M = ~8 fps@ Autodesk 3ds max 2011 viewport
d3d dx10 + sandy bridge integrated graphics = ~17 fps @ same file ( more than twice the performance from integrated graphics...)
opengl + gtx 460m = 0.63 fps @ same file (lol?)

EDIT: Also, if you're talking AutoCAD (but you said engineering, so probably audoesk inventor or solidworks?), then you're beyond SOL with the 460m: Autocad 2011 doesn't even detect the nvidia card (if the system has optimus)

Do not purchase whichever config had the 400 series nvidia card if you want to see some actual performance in CAD.

 

oh ok cool. thanks for the advice. yea i kinda want it more for gaming.

hey thanks alot man i had no idea the 400 series dont work well with autocad and that is what i will be using. so i guess i am going with the m17x. thanks guys for you input.