I've the same problem. Disabling the card switching definitely works but this is no long term solution.
*** Panic Report ***
panic(cpu 0 caller 0xffffff7f9013bf63): "GPU Panic: [<None>] 3 0 a0 d9 9 8 0 3 : NVRM[0/1:0:0]: Read Error 0x00000144: CFG 0xffffffff 0xffffffff 0xffffffff, BAR0 0x104000000 0xffffff811ec0e000 0x0e7150a2, D0, P1/4\n"@/SourceCache/AppleGraphicsControl/AppleGraphicsControl-3.7.21/src/Apple MuxControl/kext/GPUPanic.cpp:127
Backtrace (CPU 0), Frame : Return Address
0xffffff80f0797ba0 : 0xffffff800d53a811
0xffffff80f0797c20 : 0xffffff7f9013bf63
0xffffff80f0797d00 : 0xffffff7f8e19ad28
0xffffff80f0797dc0 : 0xffffff7f8e2651b6
0xffffff80f0797e00 : 0xffffff7f8e49aacc
0xffffff80f0797e20 : 0xffffff7f8e1a16fe
0xffffff80f0797ec0 : 0xffffff7f8e1507b0
0xffffff80f0797ee0 : 0xffffff800dada76f
0xffffff80f0797f10 : 0xffffff7f8dd3f79d
0xffffff80f0797f50 : 0xffffff7f901c0db4
0xffffff80f0797f60 : 0xffffff7f901c8eeb
0xffffff80f0797f80 : 0xffffff800d61dd25
0xffffff80f0797fd0 : 0xffffff800d63a609
0xffffff811ea6bf40 : 0xffffff800d5514bb
0xffffff811ea6bf90 : 0xffffff800d551970
0xffffff811ea6bfb0 : 0xffffff800d6192c7
Kernel Extensions in backtrace:
com.apple.iokit.IOPCIFamily(2.9)[766FC23F-452C-3B74-951C-598BB17BCF06]@0xffffff 7f8dd24000->0xffffff7f8dd52fff
com.apple.driver.AppleACPIPlatform(3.1)[7CBF1E7C-6810-3D0B-B5D2-49B649192B1F]@0 xffffff7f901ba000->0xffffff7f90218fff
dependency: com.apple.iokit.IOACPIFamily(1.4)[70E2B65E-A91A-3522-A1A0-79FD63EABB4C]@0xfffff f7f8eb9d000
dependency: com.apple.iokit.IOPCIFamily(2.9)[766FC23F-452C-3B74-951C-598BB17BCF06]@0xffffff 7f8dd24000
com.apple.driver.AppleMuxControl(3.7.21)[32B7E2DE-1F9D-3555-B687-7A76A62B81D2]@ 0xffffff7f9012d000->0xffffff7f90140fff
dependency: com.apple.driver.AppleGraphicsControl(3.7.21)[62689710-EEA7-307A-AC83-B8F25DA88 A6A]@0xffffff7f90125000
dependency: com.apple.iokit.IOACPIFamily(1.4)[70E2B65E-A91A-3522-A1A0-79FD63EABB4C]@0xfffff f7f8eb9d000
dependency: com.apple.iokit.IOPCIFamily(2.9)[766FC23F-452C-3B74-951C-598BB17BCF06]@0xffffff 7f8dd24000
dependency: com.apple.iokit.IOGraphicsFamily(2.4.1)[6D99A3BE-D531-3780-880B-13F2FC894A4A]@0 xffffff7f8e0ed000
dependency: com.apple.driver.AppleBacklightExpert(1.1.0)[0183904C-6A16-32C4-9405-EEFD7F820B 02]@0xffffff7f90128000
com.apple.nvidia.driver.NVDAResman(10.0)[53CC0E05-7382-336C-8239-AE884D6CA71A]@ 0xffffff7f8e14a000->0xffffff7f8e3bffff
dependency: com.apple.iokit.IOPCIFamily(2.9)[766FC23F-452C-3B74-951C-598BB17BCF06]@0xffffff 7f8dd24000
dependency: com.apple.iokit.IONDRVSupport(2.4.1)[F4738C55-B507-3627-A9CA-3D29A5230A03]@0xff ffff7f8e134000
dependency: com.apple.iokit.IOGraphicsFamily(2.4.1)[6D99A3BE-D531-3780-880B-13F2FC894A4A]@0 xffffff7f8e0ed000
dependency: com.apple.AppleGraphicsDeviceControl(3.7.21)[4700601D-3FEB-3B86-B2BA-8D71AF84D1 C4]@0xffffff7f8e144000
com.apple.nvidia.driver.NVDAGK100Hal(10.0)[DC43029D-568A-3B7C-976B-E922C17F5143 ]@0xffffff7f8e3cb000->0xffffff7f8e578fff
dependency: com.apple.nvidia.driver.NVDAResman(10.0.0)[53CC0E05-7382-336C-8239-AE884D6CA71A ]@0xffffff7f8e14a000
dependency: com.apple.iokit.IOPCIFamily(2.9)[766FC23F-452C-3B74-951C-598BB17BCF06]@0xffffff 7f8dd24000
Model: MacBookPro10,1, BootROM MBP101.00EE.B05, 4 processors, Intel Core i7, 2.4 GHz, 8 GB, SMC 2.3f36
Graphics: Intel HD Graphics 4000, Intel HD Graphics 4000, Built-In
Graphics: NVIDIA GeForce GT 650M, NVIDIA GeForce GT 650M, PCIe, 1024 MB
Memory Module: BANK 0/DIMM0, 4 GB, DDR3, 1600 MHz, 0x802C, 0x384A54463235363634485A2D3147364D3120
Memory Module: BANK 1/DIMM0, 4 GB, DDR3, 1600 MHz, 0x802C, 0x384A54463235363634485A2D3147364D3120