Hello to all TechPowerUp forum people! First, I want to excuse for my english, it's not my native language. I came here because I saw a lot of very talented people that surely can help me with a problem. I'll try to be brief and precise. Lately, some of the games I play suddenly put my monitor "out of range" or simply in a black screen. i.e: Let's say I'm playing Serious Sam 2, it's maybe 5 minutes and Bam, black screen, out of range. I can hear the music and sound going for 3 seconds more before freezing and then the machine reboots... Curious thing is, some games do this, others don't. Games that don't have the problem: Assassins Creed Brotherhood. Metro 2033 (Most demanding game I ever had) STALKER: Clear Sky. Rage. Games that eventually hang: Fallout 3. Any Serious Sam (Be it SSam 2, First encounter HD, Second encounter HD) Borderlands also did this but I tried it again recently and played for an hour without problems... I checked PSU voltages and they don't seem to drop when the screen goes black. Tested with a multimeter, Voltage is steady at 12V. I also monitored GPU temperatures and sometimes it happens at 80º degrees C, others at 85, and sometimes 90. Doesn't seem temp related... The card idles at 65. Tried forcing the cooler to 100 % speed all the time but it will hang the same. What do you suggest I try next? I'll be filling my specs now and accept any thing to try. My goal is understand what happens and learn something so I'll be willing to experiment. Thanks in advance for the help or suggestions! Regards from Argentina.