Two problems:

 

Setup:

ASUS P8Z68-V Pro/Gen3 Motherboard

 

i5 2500K 3.3 GHz 6MB Cache LGA1155 95W

 

Dual EVGA GeForce GTX560Ti SLI

 

Memory: G Skill Ripjaws Series F3-12 800 CL9D-8GBRL DDR3-1600 PC3-12800 1.5V

 

ANTEC Earthwatts 650W Max Model EA-650

 

Samsung SSD 830 Series: Primarily for FSX

H60 Water Cooler for CPU

 

Overclocked to 4.8GHz

________________________________________

 

Problem 1: Maybe 20% of the time when computer boots up, shortly after the Windows loading message and the Windows Logo appear the machine locks up. Shutting down and restarting usually goes OK.

 

Problem 2: Many videos lose sound about half or more throught the video.

 

Are these overclocking issues or Win 7/64 issues?

Your overclock is likely unstable. You should stress test with a program or two. I use Intel Burn Test set to maximum to verify the CPU's ability to crunch numbers at a given clock speed, and Prime 95 set to blend to test the memory's functionality at the given clock speed. If you find instability, report the results and you'll get some advice on how to fix it. Usually the answer is more Vcore, but that assumes you haven't pushed too far already and your temperatures are in the acceptable range.

I suspected as much. Cooling doesn't seem to be a problem so maybe the Vcore change will help. Thanks

Did some BIOS adjustments and with rare BSOD am running 4.5 GHz OK with temps running in low 50s using FSX.