Crysis, Which Computer Should I Buy?

I want to buy a laptop to play Crysis, but given my budget I must choose between these two. Which should i choose?
dell inspiron 1720
SYSTEM COLOR Jet Black
PROCESSOR Intel® Core™ 2 Duo T8300 (2.4GHz/800Mhz FSB/3MB cache)
OPERATING SYSTEM Genuine Windows Vista® Home Premium Edition
DISPLAY Glossy, high contrast, widescreen 17.0 inch display (1440 x 900)
VIDEO CARD 256MB NVIDIA® GeForce® 8600M GT
MEMORY 3GB Shared Dual Channel DDR2 at 667MHz
HARD DRIVE Size: 250GB SATA Hard Drive (5400RPM)
OPTICAL DRIVE CD / DVD writer (DVD+/-RW Drive)
$1,423 or
Alienware area 51m9750
512MB NVIDIA® GeForce® 8700M GT – Enables DirectX® 10 Graphics
17″ WideXGA+ 1440 x 900 LCD – Stealth Black
Intel® Core™ 2 Duo T5500 1.66GHz 2MB Cache 667MHz FSB
1GB Dual Channel DDR2 SO-DIMM at 667MHz – 2 x 512MB
Windows Vista® Home Premium
80GB 7,200RPM (8MB Cache)
24x Burner (DVD-ROM, CD-RW)
$1,599
What’s more important? RAM of the computer or the memory of the video card? thanks~!

Which Laptop Would Be Best For Playing Crysis Or Other High-end Computer Games?

1) A Gateway 173-X at $1349http://www.gateway.com/systems/product/5…
Genuine Microsoft® Windows Vista® Ultimate (64-bit) SP1
Intel® Core™2 Duo Processor1 T7500 (2.20GHz, 800MHz, 4MB L2 Cache)
4096MB 667MHz DDR2 SDRAM (2-2048MB modules)
200GB 7200rpm Serial ATA hard drive w/ 16MB Cache2
NVIDIA® GeForce® 8800M GTS with 512MB of GDDR3 discrete video memory
17.0″ WXGA+ Ultrabright TFT Active Matrix (1440 x 900 max. resolution)
Intel® PM965 Chipset
8x Multi-Format Dual Layer DVDRW with DVD-RAM featuring
2) or a Dell XP at $1,274.00
Intel® Core™ 2 Duo T5850 (2.16GHz/667Mhz FSB/2MB cache)
Genuine Windows Vista® Home Premium Edition SP1
Glossy, widescreen 15.4 inch LCD (1280×800) & 2.0 MP Camera
4GB Shared Dual Channel DDR2 SDRAM at 667MHz (2 Dimms)
Size: 320GB 5400rpm SATA Hard Drive
Slot Load DVD+/-RW (DVD/CD read/write)
256MB NVIDIA® GeForce® 8600M GT
What are the 4MB and 2MB Caches for, anyway?