Mountain Lion 10.8.4 freezes unexpectedly

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Hi everyone! I've got a problem and have no idea how to fix it and even what is causing it. The problem is that my PC with ML 10.8.4 can freeze at any moment and even the Reset button makes it shutdown (not restart) after 3-4 secs. When not frozen, the button works as it should. So, what exactly happens? For example, I'm browsing some site with Chrome, move cursor and it doesn't move. When I press the Reset button, the computer thinks for about 3-4 seconds and shuts down. If I turn it on again, everything works fine. These freezes can happen once a day or more, but can pass by. They don't depend on the program I'm using. I can launch nothing, wait for some hours and get a freeze. Now, something about my configuration.

 

MB: Asus P8Z77-V LX

Graphics: Gigabyte Nvidia GTX 670 2GB

RAM: Hynix 4 x 4GB

OS: ML 10.8.4 original
Bootloader: Clover v1958.

DSDT: Original + general fixes.

SSDT: Don't use it.

Mac Profile: iMac12,2 with processor states changed to MacPro3,1's. 

AGPM: edited, profile for my video card added. 

Logs: I don't see any errors there. Usually the last records before the freeze are something like: 

19.08.13 18:11:19,723 com.apple.backupd[4990]: Created new backup: 2013-08-19-181119
19.08.13 18:11:20,320 com.apple.backupd[4990]: Could not back up OS X Recovery to /Volumes/Data/Backups.backupdb: Error Domain=NSCocoaErrorDomain Code=-69737 "Unable to mount recovery partition" UserInfo=0x7fe2f9e7ef50 {NSLocalizedDescription=Unable to mount recovery partition}
19.08.13 18:11:23,485 com.apple.backupd[4990]: Starting post-backup thinning
19.08.13 18:11:23,485 com.apple.backupd[4990]: No post-back up thinning needed: no expired backups exist
19.08.13 18:11:23,590 com.apple.backupd[4990]: Backup completed successfully.

or 

19.08.13 18:59:51,925 coreservicesd[67]: SendFlattenedData, got error #268435460 (ipc/send) timed out from ::mach_msg(), sending notification kLSNotifyApplicationDeath to notificationID=120
19.08.13 18:59:51,925 coreservicesd[67]: SendFlattenedData, got error #268435460 (ipc/send) timed out from ::mach_msg(), sending notification kLSNotifyApplicationDeath to notificationID=183
19.08.13 18:59:51,929 coreservicesd[67]: SendFlattenedData, got error #268435460 (ipc/send) timed out from ::mach_msg(), sending notification kLSNotifyApplicationDeath to notificationID=139
19.08.13 18:59:51,929 coreservicesd[67]: SendFlattenedData, got error #268435460 (ipc/send) timed out from ::mach_msg(), sending notification kLSNotifyApplicationDeath to notificationID=100
19.08.13 18:59:51,929 coreservicesd[67]: SendFlattenedData, got error #268435460 (ipc/send) timed out from ::mach_msg(), sending notification kLSNotifyApplicationDeath to notificationID=145
19.08.13 18:59:51,930 coreservicesd[67]: SendFlattenedData, got error #268435460 (ipc/send) timed out from ::mach_msg(), sending notification kLSNotifyApplicationDeath to notificationID=100
 

If someone knows what can cause the lags, please tell me, cause I got totally tired of it. If you need some info, write here. I'll try to find it.