run out of shared memory? using too much shared data

when i compile my project with cuda3.1 on GTX465, i get:
“uses too much shared data (0x4818 bytes + 0x10 bytes system, 0x4000 max)”
but the shared memory available per block on GTX465 is 48KB, i just used 16KB of that. Is there any switch i should open in order to use more shared memory?

Compile with [font=“Courier New”]-arch sm_20[/font].

thanks for the useful information :-)