I downloaded the modified CudaMiner x86.
-i 0 [b]-C 1[/b] -m 1 -H 1 -l F4x16
[2014-01-25 15:05:50] 1 miner threads started, using 'scrypt' algorithm.
[2014-01-25 15:05:50] Starting Stratum on stratum+tcp://s.eu.vertcoin.org:3333
[2014-01-25 15:05:51] Stratum detected new block
[2014-01-25 15:05:52] GPU #0: GeForce GT 540M with compute capability 2.1
[2014-01-25 15:05:52] GPU #0: interactive: 0, tex-cache: 1D, single-alloc: 1
[2014-01-25 15:05:52] GPU #0: using launch configuration F4x16
[2014-01-25 15:05:52] GPU #0: GeForce GT 540M, 4.05 khash/s
[2014-01-25 15:05:53] GPU #0: GeForce GT 540M, 15.28 khash/s
[2014-01-25 15:05:53] accepted: 1/1 (100.00%), 15.28 khash/s (yay!!!)
[2014-01-25 15:06:03] GPU #0: GeForce GT 540M, 17.27 khash/s
[2014-01-25 15:06:03] accepted: 2/2 (100.00%), 17.27 khash/s (yay!!!)
[2014-01-25 15:06:05] GPU #0: GeForce GT 540M, 16.61 khash/s
[2014-01-25 15:06:06] accepted: 3/3 (100.00%), 16.61 khash/s (yay!!!)
-i 0 [b]-C 2[/b] -m 1 -H 1 -l F4x16
[2014-01-25 15:06:13] 1 miner threads started, using 'scrypt' algorithm.
[2014-01-25 15:06:13] Starting Stratum on stratum+tcp://s.eu.vertcoin.org:3333
[2014-01-25 15:06:13] Stratum detected new block
[2014-01-25 15:06:14] GPU #0: GeForce GT 540M with compute capability 2.1
[2014-01-25 15:06:14] GPU #0: interactive: 0, tex-cache: 2D, single-alloc: 1
[2014-01-25 15:06:14] GPU #0: using launch configuration F4x16
[2014-01-25 15:06:15] GPU #0: GeForce GT 540M, 4.08 khash/s
[2014-01-25 15:06:20] GPU #0: GeForce GT 540M result does not validate on CPU (i=87, s=0)!
[2014-01-25 15:06:25] GPU #0: GeForce GT 540M result does not validate on CPU (i=1785, s=0)!
[2014-01-25 15:06:26] GPU #0: GeForce GT 540M result does not validate on CPU (i=1626, s=0)!
[2014-01-25 15:06:27] GPU #0: GeForce GT 540M, 19.33 khash/s
[2014-01-25 15:06:29] GPU #0: GeForce GT 540M result does not validate on CPU (i=1041, s=1)!
[2014-01-25 15:06:29] GPU #0: GeForce GT 540M result does not validate on CPU (i=375, s=1)!
I hashrate I get with -C 2 while mining other currencies is ~ 34.5 kH/s.