Freeze après retour de veille

Bonjour,

ça fait maintenant quelques mois que je rencontre le problème suivant, dans 2 cas :
1. j'ouvre de gros logiciels en même temps (ou simplement Photoshop en temps en temps)
2. je ressors du mode veille après une longue durée (environ 2h, car après quelques minutes de veille, aucun problème).

Dans ces deux cas, je me retrouve en face de l'écran "You need to shutdown your computer. Hold down the power button for a few seconds to restart.".

En le redémarrant, voici le rapport (je tourne sous OS Snow leopard, MacBook Pro):

Interval Since Last Panic Report:  18672 sec
Panics Since Last Report:          2
Anonymous UUID:                    60E6A8C9-3A59-49AF-984B-D3674DE67F3A

Wed Jun 13 21:47:27 2012
panic(cpu 2 caller 0x9d4c9b): NVRM[0/1:0:0]: Read Error 0x00000100: CFG 0xffffffff 0xffffffff 0xffffffff, BAR0 0xc0000000 0x7fa04000 0x0a5480a2, D0, P0/4
Backtrace (CPU 2), Frame : Return Address (4 potential args on stack)
0x5c7d3888 : 0x21b837 (0x5dd7fc 0x5c7d38bc 0x223ce1 0x0) 
0x5c7d38d8 : 0x9d4c9b (0xbea28c 0xc5a800 0xbf8e60 0x0) 
0x5c7d3978 : 0xaef608 (0x969b804 0x9764004 0x100 0x8508800) 
0x5c7d39c8 : 0xae6601 (0x9764004 0x100 0x5c7d39f8 0x9c4778) 
0x5c7d39f8 : 0x16d59a6 (0x9764004 0x100 0x438004ee 0x2b1f6a) 
0x5c7d3b38 : 0xb0e2b5 (0x9764004 0x91a5004 0x0 0x0) 
0x5c7d3b78 : 0x9dde7c (0x9764004 0x91a5004 0x0 0x0) 
0x5c7d3c18 : 0x9da55b (0x0 0x9 0x0 0x0) 
0x5c7d3dc8 : 0x9dc42a (0x0 0x600d600d 0x702a 0x5c7d3df8) 
0x5c7d3e98 : 0x970582 (0xc1d00017 0xaa910001 0x20802040 0x5c7d3ee0) 
0x5c7d3ef8 : 0xd3257d (0x8ed3400 0x5c7d3f4c 0x0 0x7) 
0x5c7d3f58 : 0xd3271a (0x8ec6000 0xd39e54 0x5c7d3f78 0x2a45c9) 
0x5c7d3f78 : 0x230235 (0x8ec6000 0x0 0x0 0x0) 
0x5c7d3fc8 : 0x2a179c (0x863ea0 0x0 0x10 0xa138524) 
     Kernel Extensions in backtrace (with dependencies):
        com.apple.driver.AGPM(100.12.31)@0xd2f000->0xd39fff
           dependency: com.apple.iokit.IOGraphicsFamily(2.2.1)@0x93f000
           dependency: com.apple.iokit.IONDRVSupport(2.2.1)@0x961000
           dependency: com.apple.iokit.IOPCIFamily(2.6.5)@0x928000
        com.apple.nvidia.nv50hal(6.4.0)@0x159f000->0x19b3fff
           dependency: com.apple.NVDAResman(6.4.0)@0x96e000
        com.apple.NVDAResman(6.4.0)@0x96e000->0xc5bfff
           dependency: com.apple.iokit.IOPCIFamily(2.6.5)@0x928000
           dependency: com.apple.iokit.IONDRVSupport(2.2.1)@0x961000
           dependency: com.apple.iokit.IOGraphicsFamily(2.2.1)@0x93f000

BSD process name corresponding to current thread: kernel_task

Mac OS version:
10K549

Kernel version:
Darwin Kernel Version 10.8.0: Tue Jun  7 16:33:36 PDT 2011; root:xnu-1504.15.3~1/RELEASE_I386
System model name: MacBookPro6,2 (Mac-F22586C8)

System uptime in nanoseconds: 2195670648174
unloaded kexts:
com.apple.driver.AppleUSBUHCI	4.2.0 (addr 0x142d000, size 0x65536) - last unloaded 233616478257
loaded kexts:
com.sophos.kext.sav	7.3.0
com.apple.driver.AppleHWSensor	1.9.3d0 - last loaded 46583303780
com.apple.filesystems.autofs	2.1.0
com.apple.driver.AGPM	100.12.31
com.apple.driver.AppleMikeyHIDDriver	1.2.0
com.apple.driver.AppleHDA	2.0.5f14
com.apple.driver.AppleMikeyDriver	2.0.5f14
com.apple.driver.AppleUpstreamUserClient	3.5.7
com.apple.driver.AppleMCCSControl	1.0.20
com.apple.driver.AudioAUUC	1.57
com.apple.driver.AppleIntelHDGraphics	6.4.0
com.apple.driver.AppleIntelHDGraphicsFB	6.4.0
com.apple.driver.SMCMotionSensor	3.0.1d2
com.apple.Dont_Steal_Mac_OS_X	7.0.0
com.apple.driver.AudioIPCDriver	1.1.6
com.apple.GeForce	6.4.0
com.apple.driver.AppleLPC	1.5.1
com.apple.driver.AppleGraphicsControl	2.10.6
com.apple.kext.AppleSMCLMU	1.5.2d10
com.apple.driver.ACPI_SMC_PlatformPlugin	4.7.0a1
com.apple.driver.AppleUSBTCButtons	201.6
com.apple.driver.AppleUSBCardReader	2.6.1
com.apple.driver.AppleIRController	303.8
com.apple.driver.AppleUSBTCKeyboard	201.6
com.apple.iokit.SCSITaskUserClient	2.6.8
com.apple.BootCache	31.1
com.apple.AppleFSCompression.AppleFSCompressionTypeZlib	1.0.0d1
com.apple.iokit.IOAHCIBlockStorage	1.6.4
com.apple.driver.AppleFWOHCI	4.7.3
com.apple.driver.AppleUSBHub	4.2.4
com.apple.driver.AirPortBrcm43224	428.42.4
com.apple.driver.AppleEFINVRAM	1.4.0
com.apple.driver.AppleSmartBatteryManager	160.0.0
com.apple.driver.AppleAHCIPort	2.1.7
com.apple.iokit.AppleBCM5701Ethernet	3.0.5b8
com.apple.driver.AppleUSBEHCI	4.2.4
com.apple.driver.AppleACPIButtons	1.3.6
com.apple.driver.AppleRTC	1.3.1
com.apple.driver.AppleHPET	1.5
com.apple.driver.AppleSMBIOS	1.7
com.apple.driver.AppleACPIEC	1.3.6
com.apple.driver.AppleAPIC	1.4
com.apple.driver.AppleIntelCPUPowerManagementClient	142.6.0
com.apple.security.sandbox	1
com.apple.security.quarantine	0
com.apple.nke.applicationfirewall	2.1.14
com.apple.driver.AppleIntelCPUPowerManagement	142.6.0
com.apple.driver.DspFuncLib	2.0.5f14
com.apple.driver.AppleProfileReadCounterAction	17
com.apple.driver.AppleProfileTimestampAction	10
com.apple.driver.AppleProfileThreadInfoAction	14
com.apple.driver.AppleProfileRegisterStateAction	10
com.apple.driver.AppleProfileKEventAction	10
com.apple.driver.AppleProfileCallstackAction	20
com.apple.driver.AppleSMBusController	1.0.10d0
com.apple.nvidia.nv50hal	6.4.0
com.apple.iokit.IOFireWireIP	2.0.3
com.apple.iokit.IOSurface	74.2
com.apple.iokit.IOBluetoothSerialManager	2.4.5f3
com.apple.iokit.IOSerialFamily	10.0.3
com.apple.iokit.IOAudioFamily	1.8.3fc2
com.apple.kext.OSvKernDSPLib	1.3
com.apple.driver.AppleHDAController	2.0.5f14
com.apple.iokit.IOHDAFamily	2.0.5f14
com.apple.NVDAResman	6.4.0
com.apple.iokit.AppleProfileFamily	41
com.apple.driver.AppleSMBusPCI	1.0.10d0
com.apple.driver.AppleBacklightExpert	1.0.1
com.apple.iokit.IONDRVSupport	2.2.1
com.apple.iokit.IOGraphicsFamily	2.2.1
com.apple.driver.AppleSMC	3.1.0d5
com.apple.driver.IOPlatformPluginFamily	4.7.0a1
com.apple.driver.BroadcomUSBBluetoothHCIController	2.4.5f3
com.apple.driver.AppleUSBBluetoothHCIController	2.4.5f3
com.apple.iokit.IOBluetoothFamily	2.4.5f3
com.apple.iokit.IOSCSIBlockCommandsDevice	2.6.8
com.apple.iokit.IOUSBMassStorageClass	2.6.7
com.apple.driver.AppleUSBMultitouch	207.7
com.apple.iokit.IOUSBHIDDriver	4.2.0
com.apple.driver.AppleUSBMergeNub	4.2.4
com.apple.driver.AppleUSBComposite	3.9.0
com.apple.iokit.IOSCSIMultimediaCommandsDevice	2.6.8
com.apple.iokit.IOBDStorageFamily	1.6
com.apple.iokit.IODVDStorageFamily	1.6
com.apple.iokit.IOCDStorageFamily	1.6.1
com.apple.driver.XsanFilter	402.1
com.apple.iokit.IOAHCISerialATAPI	1.2.6
com.apple.iokit.IOSCSIArchitectureModelFamily	2.6.8
com.apple.iokit.IOFireWireFamily	4.2.6
com.apple.iokit.IOUSBUserClient	4.2.4
com.apple.iokit.IO80211Family	320.1
com.apple.iokit.IOAHCIFamily	2.0.6
com.apple.iokit.IONetworkingFamily	1.10
com.apple.iokit.IOUSBFamily	4.2.4
com.apple.driver.AppleEFIRuntime	1.4.0
com.apple.iokit.IOHIDFamily	1.6.6
com.apple.iokit.IOSMBusFamily	1.1
com.apple.kext.AppleMatch	1.0.0d1
com.apple.security.TMSafetyNet	6
com.apple.driver.DiskImages	289
com.apple.iokit.IOStorageFamily	1.6.3
com.apple.driver.AppleACPIPlatform	1.3.6
com.apple.iokit.IOPCIFamily	2.6.5
com.apple.iokit.IOACPIFamily	1.3.0
Model: MacBookPro6,2, BootROM MBP61.0057.B0C, 2 processors, Intel Core i5, 2.53 GHz, 4 GB, SMC 1.58f16
Graphics: NVIDIA GeForce GT 330M, NVIDIA GeForce GT 330M, PCIe, 256 MB
Graphics: Intel HD Graphics, Intel HD Graphics, Built-In, 288 MB
Memory Module: global_name
AirPort: spairport_wireless_card_type_airport_extreme (0x14E4, 0x93), Broadcom BCM43xx 1.0 (5.10.131.42.4)
Bluetooth: Version 2.4.5f3, 2 service, 19 devices, 1 incoming serial ports
Network Service: AirPort, AirPort, en1
Serial ATA Device: Hitachi HTS545050B9SA02, 465.76 GB
Serial ATA Device: MATSHITADVD-R   UJ-898
USB Device: Hub, 0x0424  (SMSC), 0x2514, 0xfa100000 / 2
USB Device: Internal Memory Card Reader, 0x05ac  (Apple Inc.), 0x8403, 0xfa130000 / 5
USB Device: Apple Internal Keyboard / Trackpad, 0x05ac  (Apple Inc.), 0x0237, 0xfa120000 / 4
USB Device: BRCM2070 Hub, 0x0a5c  (Broadcom Corp.), 0x4500, 0xfa110000 / 3
USB Device: Bluetooth USB Host Controller, 0x05ac  (Apple Inc.), 0x8218, 0xfa113000 / 8
USB Device: Hub, 0x0424  (SMSC), 0x2514, 0xfd100000 / 2
USB Device: Built-in iSight, 0x05ac  (Apple Inc.), 0x8507, 0xfd110000 / 4
USB Device: IR Receiver, 0x05ac  (Apple Inc.), 0x8242, 0xfd120000 / 3

Si quelqu'un pouvait m'aider, je serais extrêmement ravis.

Bonne journée