GTX 275 or 9800GT Ultimate

Hello, graphic community.

I wanted to as a question which i can't seem to find the answer anywhere.

I am in front of a dilemma.

Currently i have ASUS EN9800GT Ultimate with specs taken from their site:

Bus Standard PCI Express 2.0
Video Memory DDR3 512MB
Engine Clock 725 MHz
Shader Clock 1.75 GHz
Memory Clock 2.0 GHz ( 1.0 GHz DDR3 )
RAMDAC 400MHz
Memory Interface 256-bit

But recently had the oportunity to buy a new, better (or i think) one ASUS ENGTX 275

Oddly the specs in some points are lower:

Bus Standard PCI Express 2.0
Video Memory DDR3 896MB
Engine Clock 633 MHz
Shader Clock 1404 MHz
Memory Clock 2.268 GHz ( 1.134 GHz DDR3 )
Memory Interface 448-bit

As i couldn't find any additional info my question is: Is it worth it? And if i take the GTX 270 i am going to end up with even slower Graphics card?

Thanks for the answers in advance

Clock speeds dont matter unless your talking about the same series of cards. The GPU on the 275 is far superior.

i'll find comparisons between stock card and not overclock which is the case with 9800GT Ulti