That dell is slightly cheaper, but that is due to it using a Geforce GT 525M, which compared to a GT 425M. The GTX 460M in the ASUS laptop does make up for the slower CPU and higher price
GT 525M Specs:
Codename N12P-GE
Pipelines 96 - unified
Core Speed * 600 MHz
Shader Speed * 1200 MHz
Memory Speed * 900 MHz
Memory Bus Width 128 Bit
Memory Type GDDR5, DDR3
Max. Amount of Memory 1536 MB
Shared Memory no
DirectX DirectX 11, Shader 5.0
technology 40 nm
Notebook Size medium sized
Roughly Compares to Radeon 5650M
GTX 460M Specs:
Codename GF106
Pipelines 192 - unified
Core Speed * 675 MHz
Shader Speed * 1350 MHz
Memory Speed * 1250 MHz
Memory Bus Width 192 Bit
Memory Type GDDR5
Max. Amount of Memory 1536 MB
Shared Memory no
DirectX DirectX 11, Shader 5.0
technology 40 nm
Notebook Size large
Roughly compares to Radeon 5870M