Thought this might help some with systems similar to mine. I had my system overclocked to 4.8GHz for several weeks and it appeared to be stable as I ran Prime95 and 3dMark11 successfully several times. But recently I started to get crashes while surfing the Internet or running FSX. I reverted to the optimized default settings (3.5GHz). No more crashes and FSX actually ran very well on those settings (FSX likes a lot of CPU cores...). I did some research today on the crashes I had been getting and went back into the BIOS and hit the Extreme setting button ASUS has for automatic overclocking. It successfully got me to 4.4GHz and the system appeared stable. Then, suddenly a BSOD and the Event Viewer stated I bugcheck code 1e caused the crash and Google stated that it was related to hardware - specifically memory. I went back into the BIOS and changed the memory setting from DDR3-1685MHz to Auto and restarted the system. I ran 3dMark11 and no crashes. I ran Prime95 and no crash but after running for about 20 minutes, I got an error message stating Prime95 was no longer responding and I had to close the program. I checked the results in the Prime95 folder and it stated: FATAL ERROR: Rounding was 0.4987792969, expected less than 0.4; Hardware failure detected, consult stress.txt file. The stress file basically stated, "yes, you can operate your system for days, weeks, months with no problems but eventually you're going to get a sudden unexplained crash and you need to fix it. I decided to fix it now so checked the timing for my memory. When I opened the memory settings in the BIOS, they were way off the settings shown in "system information by Gabriel Topala" program (freeware off the Internet). They were like 9-2-8-24-2 when my the system information program said they should be 9-9-9-24-33 at 666.7MHz, at 1.5 volts (the BIOS was setting it at 1.65 volts). Changed those figures, saved, and restarted then ran Prime95 for about 2 hours and no crashes or errors. Checked the results in the Prime95 folder and saw no errors whatsoever. All tests were successful. So, in my case it was the memory timing and voltage settings. Hope this helps someone else with their sudden Sandy Bridge crashes.Best regards,Jim

My initial problem was RAM related, but once I enabled XMP with my sticks it worked fine.As far as the 4+ OCing goes... no idea... I'm just staying at 4 though part of me wants to try for more (human nature, always wanting more pfff)

Ryan, do you have your memory timings set at 'auto', or have you set them manually in the bios? I am afraid to touch mine, so they are all still at 9-9-9-24 1333....

You should always enter your memory timing and voltage manually in bios to make sure they are running at manuf. spec. always.

You should always enter your memory timing and voltage manually in bios to make sure they are running at manuf. spec. always.

...I understand that; I was asking, because I have the Gigabyte GA P67a-ud3-b3 mobo, with a 2600k, and 8gb of vengeance 1866-speed ram timed at 9-10-9-27, and 1.5v. My 'puter is oc'd to 4.6, stable. If i attempt to change any memory setting in the bios, the computer will not boot. Or, it will bootloop. Or, it won't even post. Or, it will sprout legs and run out the door screaming bloody murder. But it will not allow me to make manual timing and speed settings in the bios without throwing a hissy fit. So, that is why I asked Ryan specifically since his setup is **kinda** close to mine hardware-wise...

...I understand that; I was asking, because I have the Gigabyte GA P67a-ud3-b3 mobo, with a 2600k, and 8gb of vengeance 1866-speed ram timed at 9-10-9-27, and 1.5v. My 'puter is oc'd to 4.6, stable. If i attempt to change any memory setting in the bios, the computer will not boot. Or, it will bootloop. Or, it won't even post. Or, it will sprout legs and run out the door screaming bloody murder. But it will not allow me to make manual timing and speed settings in the bios without throwing a hissy fit. So, that is why I asked Ryan specifically since his setup is **kinda** close to mine hardware-wise...

I do not have a P67 setup and I'm not sure I understand what you'r asking, is the memory in bios showing at rated speed and timing? I'm asking because you said... If i attempt to change any memory setting in the bios, the computer will not boot. I'm assuming that if you want to change it it's because it's not running at rated speed or if it is why do you want to change it....I'm confuse.You also said....But it will not allow me to make manual timing and speed settings in the bios without throwing a hissy fit....if I'm not mistaking you probably have a setting like Dram timing selectable with auto, quick and expert for your memory if you do select expert and set your memory timing manually...just trying to help here but like I said I don't have the P67 system.Good luck.

I have the Gigabyte GA P67a-ud3-b3 mobo, with a 2600k, and 8gb of vengeance 1866-speed ram timed at 9-10-9-27, and 1.5v. My 'puter is oc'd to 4.6, stable. If i attempt to change any memory setting in the bios, the computer will not boot. Or, it will bootloop. Or, it won't even post. Or, it will sprout legs and run out the door screaming bloody murder. But it will not allow me to make manual timing and speed settings in the bios without throwing a hissy fit.

My Gigabyte board seemed very temperamental with memory settings as well. I mean it wouldn't even let me make reasonable changes! I eventually gave up on trying to overclock my memory with it. Luckily, it doesn't really make much difference for FSX anyhow.

My Gigabyte board seemed very temperamental with memory settings as well. I mean it wouldn't even let me make reasonable changes! I eventually gave up on trying to overclock my memory with it. Luckily, it doesn't really make much difference for FSX anyhow.

Memory overclocking is not as easy as overclocking your CPU, overclocking your memory mean raising the MHz trying to keep them at the same timing/ loosening the timing or keeping the MHz at manuf spec. and lowering the timing or both raising the MHz and lowering the timing (the last one is more difficult to achieve), in any case you will probably have to raise the rams voltage, the QPI/vtt or both at the same time.Not all memory will overclock, depending of the manuf. some will play nice and other will give you hell no matter what you will try, my memory is rated at 2000MHz 7-7-7-21 2T IRFC 112, I can raise mine up to 2133MHz but I have to set the timing at 9-9-9-27 to have them stable NOT AS GOOD as keeping them at 2004MHz 7-7-6-20 1T, IRFC at 92, it does take a lot of testing to squeeze all the juice you can out of your hardware but a little here and a little there add up better perf. (not only for FSX).With all due respect I do not agree with your statement "Luckily, it doesn't really make much difference for FSX anyhow."..you may not see a huge difference but in my case (as it should for everybody) high MHz and low CAS did take some of the stutterings I had away in my FSX, is my FSX perfect...no...but I can assure you that I see a difference with my rams as I have them set compare to higher MHz at 9-9-9-27, again not a big difference but some.

Memory overclocking is not as easy as overclocking your CPU, overclocking your memory mean raising the MHz trying to keep them at the same timing/ loosening the timing or keeping the MHz at manuf spec. and lowering the timing or both raising the MHz and lowering the timing (the last one is more difficult to achieve), in any case you will probably have to raise the rams voltage, the QPI/vtt or both at the same time.Not all memory will overclock, depending of the manuf. some will play nice and other will give you hell no matter what you will try, my memory is rated at 2000MHz 7-7-7-21 2T IRFC 112, I can raise mine up to 2133MHz but I have to set the timing at 9-9-9-27 to have them stable NOT AS GOOD as keeping them at 2004MHz 7-7-6-20 1T, IRFC at 92, it does take a lot of testing to squeeze all the juice you can out of your hardware but a little here and a little there add up better perf. (not only for FSX).With all due respect I do not agree with your statement "Luckily, it doesn't really make much difference for FSX anyhow."..you may not see a huge difference but in my case (as it should for everybody) high MHz and low CAS did take some of the stutterings I had away in my FSX, is my FSX perfect...no...but I can assure you that I see a difference with my rams as I have them set compare to higher MHz at 9-9-9-27, again not a big difference but some.

...Thanks for the tip; It worked!! I must have missed something the first time around, but now all is good. Much appreciated.

My pc has DDR1800 mhz memory .First I tried with 1866 mhz and 9-9-9-27 timings.Later I read more about timing settings and now I am running the same memory at 1480 mhz and 6-6-6-24 timings. That is faster !My mobo got difficulties with higher clock settings so I clocked back, but also lowerd the timings for better results. Here an overview :

You should always enter your memory timing and voltage manually in bios to make sure they are running at manuf. spec. always.

Not so on my board, since I have XMP enabled memory I've read that I need to use that setting. Mine wouldn't boot with manual settings. XMP enables the exact settings needed on my board, and stable.

Not so on my board, since I have XMP enabled memory I've read that I need to use that setting. Mine wouldn't boot with manual settings. XMP enables the exact settings needed on my board, and stable.

As I said earlier in this thread I'm not familiar with the P67, I can run my rams at default speed on my board with some adjustment on the rams and QPI/Vtt voltage, I can also enable XMP with the same timing, again not one memory set will react the same way, some play nice some don't, remember (I don't know about yours) you always pay for what you get, that is why high MHz with lower CAS cost more, you pay for performance.