Your 780 has 2304 cores. Twice the amount of cores would be K4608x32
Then I misinterpreted Christian... let's see...
Edit:
Not much change
D:\Coins\cudaminer-homebrew maxcoin\x86>cudaminer.exe -R 2 --algo=keccak -d gtx7
80 -L 256 -l K4608x32 -C 1 -i 0 -o stratum+tcp://maxpool.1gh.com:17333 -u mRv1Fg
99rny6JTkwK5BpgjBzrf9UksAoyH -p YOLO
*** CudaMiner for nVidia GPUs by Christian Buchner ***
This is version 2014-02-07 (beta)
based on pooler-cpuminer 2.3.2 (c) 2010 Jeff Garzik, 2012 pooler
Cuda additions Copyright 2013,2014 Christian Buchner
LTC donation address: LKS1WDKGED647msBQfLBHV3Ls8sveGncnm
BTC donation address: 16hJF5mceSojnTD3ZTUDqdRhDyPJzoRakM
YAC donation address: Y87sptDEcpLkLeAuex6qZioDbvy1qXZEj4
[2014-02-08 19:20:43] Starting Stratum on stratum+tcp://maxpool.1gh.com:17333
[2014-02-08 19:20:43] 1 miner threads started, using 'keccak' algorithm.
[2014-02-08 19:21:15] stratum_subscribe timed out
[2014-02-08 19:21:15] ...retry after 2 seconds
[2014-02-08 19:21:18] GPU #0: GeForce GTX 780 with compute capability 3.5
[2014-02-08 19:21:18] GPU #0: interactive: 0, tex-cache: 1D, single-alloc: 1
[2014-02-08 19:21:18] GPU #0: 32 hashes / 0.0 MB per warp.
[2014-02-08 19:21:18] GPU #0: 'K4608x32' exceeds limits for 1D cache. Using 2D c
ache instead.
[2014-02-08 19:21:18] GPU #0: using launch configuration K4608x32
[2014-02-08 19:21:19] GPU #0: cudaError 2 (out of memory) calling 'cudaMalloc((v
oid **) &tmp, mem_size)' (D:/CudaminerCompile/CudaMiner/salsa_kernel.cu line 252
)
[2014-02-08 19:21:19] GPU #0: cudaError 2 (out of memory) calling 'cudaMalloc((v
oid **) &tmp, mem_size)' (D:/CudaminerCompile/CudaMiner/salsa_kernel.cu line 253
)
[2014-02-08 19:21:19] GPU #0: cudaError 2 (out of memory) calling 'cudaMalloc((v
oid **) &tmp, mem_size)' (D:/CudaminerCompile/CudaMiner/salsa_kernel.cu line 254
)
[2014-02-08 19:21:19] GPU #0: cudaError 2 (out of memory) calling 'cudaMalloc((v
oid **) &tmp, state_size)' (D:/CudaminerCompile/CudaMiner/salsa_kernel.cu line 2
90)
[2014-02-08 19:21:19] GPU #0: cudaError 2 (out of memory) calling 'cudaMalloc((v
oid **) &tmp, state_size)' (D:/CudaminerCompile/CudaMiner/salsa_kernel.cu line 2
91)
[2014-02-08 19:21:19] GPU #0: GeForce GTX 780, 115082 khash/s
[2014-02-08 19:21:21] GPU #0: GeForce GTX 780, 155978 khash/s
[2014-02-08 19:21:21] accepted: 1/1 (100.00%), 155978 khash/s (yay!!!)
[2014-02-08 19:21:22] GPU #0: GeForce GTX 780, 164402 khash/s
[2014-02-08 19:21:23] accepted: 2/2 (100.00%), 164402 khash/s (yay!!!)
[2014-02-08 19:21:24] GPU #0: GeForce GTX 780, 157450 khash/s
[2014-02-08 19:21:25] accepted: 2/3 (66.67%), 157450 khash/s (booooo)
[2014-02-08 19:21:27] GPU #0: GeForce GTX 780, 160798 khash/s
[2014-02-08 19:21:27] GPU #0: GeForce GTX 780, 162235 khash/s
[2014-02-08 19:21:27] accepted: 3/4 (75.00%), 162235 khash/s (yay!!!)
[2014-02-08 19:21:30] GPU #0: GeForce GTX 780, 160904 khash/s
[2014-02-08 19:21:31] GPU #0: GeForce GTX 780, 164696 khash/s
[2014-02-08 19:21:31] accepted: 4/5 (80.00%), 164696 khash/s (yay!!!)
[2014-02-08 19:21:31] accepted: 5/6 (83.33%), 164696 khash/s (yay!!!)
[2014-02-08 19:21:36] GPU #0: GeForce GTX 780, 162293 khash/s
[2014-02-08 19:21:37] GPU #0: GeForce GTX 780, 152477 khash/s
[2014-02-08 19:21:38] accepted: 6/7 (85.71%), 152477 khash/s (yay!!!)
[2014-02-08 19:21:38] accepted: 7/8 (87.50%), 152477 khash/s (yay!!!)
[2014-02-08 19:21:39] GPU #0: GeForce GTX 780, 159403 khash/s
[2014-02-08 19:21:40] GPU #0: GeForce GTX 780, 164492 khash/s
[2014-02-08 19:21:41] GPU #0: GeForce GTX 780, 164346 khash/s
[2014-02-08 19:21:44] accepted: 8/9 (88.89%), 164346 khash/s (yay!!!)
[2014-02-08 19:21:44] accepted: 9/10 (90.00%), 164346 khash/s (yay!!!)
[2014-02-08 19:21:44] accepted: 10/11 (90.91%), 164346 khash/s (yay!!!)