I wonder why my NVIDIA GTX 660M can run GPUGRID flawlessly, yet it can't run HCC... anyone know why exactly? (I'd imagine full-atom simulations to be more complex than image processing).

For OpenCL, BOINC reports this.

OpenCL: NVIDIA GPU 0: GeForce GTX 660M (driver version 314.22, device version OpenCL 1.1 CUDA, 2048MB, 1940MB available, 730 GFLOPS peak)

It just says under the "notice" tab that the GPU isn't supported. As a matter of fact, it IS listed in the list of "GPUs unable to participate". I was wondering why it wasn't able though. A bunch of the cards listed are very fast and are 1.1 OpenCL capable.

looks like GeForce GT 620M isn't working too

Result Name: X0930137270567201211201623_ 1--
<core_client_version>7.0.62</core_client_version>
<![CDATA[
<message>
Kein Prozess ist am anderen Ende der Pipe.
(0xe9) - exit code 233 (0xe9)
</message>
<stderr_txt>
Commandline: projects/www.worldcommunitygrid.org/wcg_hcc1_img_7.05_windows_intelx86__nvidia_hcc1 --zipfile X0930137270567201211201623.zip --imagelist images.txt --device 0
<app_init_data>
<major_version>7</major_version>
<minor_version>0</minor_version>
<release>62</release>
<app_version>705</app_version>
<app_name>hcc1</app_name>
<acct_mgr_url>http://bam.boincstats.com/</acct_mgr_url>
<project_preferences>


<color_scheme>Tahiti Sunset</color_scheme>
<max_frames_sec>7</max_frames_sec>
<max_gfx_cpu_pct>5.0</max_gfx_cpu_pct>
</project_preferences>

<project_dir>E:\Public\BoincData/projects/www.worldcommunitygrid.org</project_dir>
<boinc_dir>E:\Public\BoincData</boinc_dir>
<wu_name>X0930137270567201211201623</wu_name>
<result_name>X0930137270567201211201623_1</result_name>
<comm_obj_name>boinc_1</comm_obj_name>
<slot>6</slot>
<wu_cpu_time>0.000000</wu_cpu_time>
<starting_elapsed_time>0.000000</starting_elapsed_time>
<using_sandbox>0</using_sandbox>
<user_total_credit>726272.211080</user_total_credit>
<user_expavg_credit>2239.950321</user_expavg_credit>
<host_total_credit>15963.390417</host_total_credit>
<host_expavg_credit>271.422156</host_expavg_credit>
<resource_share_fraction>0.250000</resource_share_fraction>
<checkpoint_period>60.000000</checkpoint_period>
<fraction_done_start>0.000000</fraction_done_start>
<fraction_done_end>1.000000</fraction_done_end>
<gpu_type>NVIDIA</gpu_type>
<gpu_device_num>0</gpu_device_num>
<gpu_opencl_dev_index>0</gpu_opencl_dev_index>
<ncpus>1.000000</ncpus>
<rsc_fpops_est>25399328680341.000000</rsc_fpops_est>
<rsc_fpops_bound>1269966434017050.000000</rsc_fpops_bound>
<rsc_memory_bound>78643200.000000</rsc_memory_bound>
<rsc_disk_bound>50000000.000000</rsc_disk_bound>
<computation_deadline>1367204368.000000</computation_deadline>
<vbox_window>0</vbox_window>
</app_init_data>
INFO: gpu_type set in init_data.xml to NVIDIA
INFO: gpu_device_num set in init_data.xml to 0
Boinc requested NVIDIA gpu device number 0
Unzipping input images ../../projects/www.worldcommunitygrid.org/X0930137270567201211201623_X0930137270567201211201623.zip
Processing jobdescription
Number of Images defined in image list is 2
Found compute platform NVIDIA Corporation
Selecting this platform
CL_DEVICE_NAME: GeForce GT 620M
CL_DEVICE_VENDOR: NVIDIA Corporation
CL_DEVICE_VERSION: 314.22
CL_DEVICE_MAX_COMPUTE_UNITS: 
CL_DEVICE_MAX_WORK_ITEM_DIMENSIONS: 3
CL_DEVICE_MAX_WORK_ITEM_SIZES: 1024 / 1024 / 64
CL_DEVICE_MAX_WORK_GROUP_SIZE: 1024
CL_DEVICE_MAX_CLOCK_FREQUENCY: 950 MHz
CL_DEVICE_ADDRESS_BITS: 32
CL_DEVICE_MAX_MEM_ALLOC_SIZE: 255 MByte
CL_DEVICE_GLOBAL_MEM_SIZE: 1023 MByte
CL_DEVICE_ERROR_CORRECTION_SUPPORT: no
CL_DEVICE_LOCAL_MEM_TYPE: local
CL_DEVICE_LOCAL_MEM_SIZE: 48 KByte
CL_DEVICE_MAX_CONSTANT_BUFFER_SIZE: 64 KByte
CL_DEVICE_QUEUE_PROPERTIES: CL_QUEUE_OUT_OF_ORDER_EXEC_MODE_ENABLE
CL_DEVICE_QUEUE_PROPERTIES: CL_QUEUE_PROFILING_ENABLE
CL_DEVICE_EXTENSIONS:
cl_khr_byte_addressable_store
cl_khr_icd
cl_khr_gl_sharing
cl_nv_d3d9_sharing
cl_nv_d3d10_sharing
cl_khr_d3d10_sharing
cl_nv_d3d11_sharing
cl_nv_compiler_options
cl_nv_device_attribute_query
cl_nv_pragma_unroll
cl_khr_global_int32_base_atomics
cl_khr_global_int32_extended_atomics
cl_khr_local_int32_base_atomics
cl_khr_local_int32_extended_atomics
cl_khr_fp64
CL_DEVICE_COMPUTE_CAPABILITY_NV: 2.1
CL_DEVICE_REGISTERS_PER_BLOCK_NV: 32768
CL_DEVICE_WARP_SIZE_NV: 32
CL_DEVICE_GPU_OVERLAP_NV: CL_TRUE
CL_DEVICE_KERNEL_EXEC_TIMEOUT_NV: CL_TRUE
CL_DEVICE_INTEGRATED_MEMORY_NV: CL_FALSE
Estimated kernel execution time = 2.44531 [sec]
ERROR: Kernel execution time estimate too high, exiting.
17:24:20 (208): called boinc_finish

</stderr_txt>

Hmmm. That card is working just fine on my Dell 8500 for WCG. But, I had to jump through hoops to get the AMD / Catalyst drivers updated. If I recall, the Dell drivers didn't work, but getting the drivers from AMD and going through a couple of version upgrades worked.
Catalyst Control Center Version 2012.0120.420.7502