The laptop overclocks its processing power automatically its called "Turbo Boost" by intel but for graphics it only downclocks itself when you arent playing a game and when you are playing a game it goes up to the default factory clock. To increase that you would use a overclocking tool such as MSI Afterburner to increase that Default clock.
Lenovo may not have any discounts but if you go here http

/www.fatwallet.com/Lenovo-coupons/code-654852/
you can get 5% cash back which would be $40 so you would only be paying $760 for the laptop not including tax.
Or if you use ebates you can get 3% cash back which is $24. I personally never used fatwallet i dont know how they work, but i have used Ebates before and i always got my cash back percentage.
That alienware is $1000. So if we compare the Y400 because its 14" same as that m14x here is what it look looks like
Alienware M14x
$1000
3rd Generation Intel® Core™ i5-3210M (3MB Cache, up to 3.1GHz w/ Turbo Boost 2.0)
Windows® 7 Home Premium, 64bit
14.0" High Def (720p/1366x768) with WLED backlight
6GB Dual Channel DDR3 SDRAM at 1600MHz
500GB 7,200 RPM SATA 3Gb/s
1 GB GDDR5 NVIDIA® GeForce® GT 650M with Optimus™
Y400
3rd Generation Intel® Core™ i5-3210M (3MB Cache, up to 3.1GHz w/ Turbo Boost 2.0)
Windows 8
14.0" High Def (720p/1366x768) with WLED backlight
8GB Dual Channel DDR3 SDRAM at 1600MHz
1TB 5400rpm HDD
2gb GDDR5 GT 650m
Price:$730
You save $270 with the lenovo, get a better graphics chip, 2gb more rap, 500gb more storage.
So what do i think about the alienware? I think its a ripoff.
Also if you go with the Y400 i recommend going for the one thats $800 because it has a much better processor. 4cores instead of 2core