Alright - so in my experience, as well as what I'm seeing on overclock.net, most people including myself require 1.4v+ to go beyond 4.6Ghz. The good news is everybody can do 4.5 or 4.6Ghz no problem, but don't be fooled, these chips do start to put out some heat at that speed. My h50, which did an excellent job of keeping my Q9550 at 3.6GHz cool, struggles with my i7-2600k at 4.6GHz. Prime 95 takes me into the mid 70s within 10 minutes. Maybe I just need to reseat my h50, I dunno. I've had 4.8Ghz at 1.45v, but I'm going to have to do something about my cooling first if I want to run that 24/7, much less test it for stability. For cooling, get an h70 or a really good air cooler. I have high hopes that overclockability will improve as new BIOS revisions are released - they're all still somewhat buggy at this point. Regardless, so far I'm quite pleased.Another word of advice (also from experience) - do not populate all 4 RAM slots! My memory, which is rated at 6-8-6-24, will run no tighter than 8-8-8-24 with four modules installed. Surprisingly, 6-8-6-24 vs 8-8-8-24 makes very little difference in MaxxMEM. Either way, I'm able to run it fine at 1.54v - so don't worry about the whole Sandy Bridge 1.5v memory requirement. If you're looking for 8GB of memory for Sandy Bridge, I think I would recommend something like this.Overall, I can't recommend the Gigabyte motherboards enough. I really like my P67A-UD5 now that I've ironed out a couple of the quirks. I don't want to make any blanket statements as to whether or not it's better than the Asus boards, but it does seem that some of the quirks the Asus boards are experiencing are much worse than what I've gone through.As far as FSX, I don't have it fully set up yet, but obviously it is way better than it was with my Q9550. That's all I can say for now. I will have more to come.

Great info, thanks!

Another word of advice (also from experience) - do not populate all 4 RAM slots! My memory, which is rated at 6-8-6-24, will run no tighter than 8-8-8-24 with four modules installed. Surprisingly, 6-8-6-24 vs 8-8-8-24 makes very little difference in MaxxMEM. Either way, I'm able to run it fine at 1.54v - so don't worry about the whole Sandy Bridge 1.5v memory requirement. If you're looking for 8GB of memory for Sandy Bridge, I think I would recommend something like this.

You take a risk anytime you use something not on the QVL. I had to rearrange my RAM in order to get all the modules working right.

I don't believe there are any 8GB sets on the QVL. I anticipated having to loosen timings to 7-8-7-24, but I didn't think it would be necessary to loosen them all the way to 8-8-8-24. I might sell what I have and find a 2x4GB set of RAM once they find their way back in stock. Or perhaps Mushkin will allow me to send them back once they have 2x4GB sets available again.

I've been saying this for days. Get the 2500K instead. What you need to do is disable HT and your temps will be fine. Of course 4 dimms will ask for more voltage, I'd rather run 2x2GB at 4.8GHz than 4x2GB at 4.6GHz, but there's really not that much of a difference.Anything over 1.375V on air for a 32nm chip is not safe in the long run.Gigabyte is well known for taking ages before having reliable & stable BIOS. There's a BETA BIOS that enables PLL overvoltage and helps with OC, but it's buggy as hell for what I've read

I've been saying this for days. Get the 2500K instead. What you need to do is disable HT and your temps will be fine. Of course 4 dimms will ask for more voltage, I'd rather run 2x2GB at 4.8GHz than 4x2GB at 4.6GHz, but there's really not that much of a difference.Anything over 1.375V on air for a 32nm chip is not safe in the long run.Gigabyte is well known for taking ages before having reliable & stable BIOS. There's a BETA BIOS that enables PLL overvoltage and helps with OC, but it's buggy as hell for what I've read

No, you misunderstood. My RAM difficulties are having no effect on my CPU overclock. That's completely seperate with Sandy Bridge as clockspeed and RAM speed are not tied together like they are on 1366. As for PLL Overvoltage, I've updated my BIOS to include it and all my comments are with respect to having it. As for what's a safe voltage... time will tell. Personally, I think anything 1.4 or below is perfectly safe. As for 2500k vs 2600k, meh, just depends on your budget. FSX isn't the only thing I use my computer for. There have been arguments on both sides regarding HT as it is, so I decided to get the 2600k so I'd be covered either way.

Well, in 1366 clock speed and ram where just as tied as in SB, it doesnt matter if you get your RAM to 1600MHz with a BCLK of 100 or 200 with half the multi, but whatever. It could be a number of things, could be what you say and SB works different with the lower BCLK, could be a BIOS that needs improving..., who knows. You could try with 2 dimms and see if you can get it stable with tighter timmings. It's up to you of course. Are you running your RAM at it's rated voltage? Vccio should be no less than 0.5V than VdimmAs for the 2600K actually it should still be running much cooler than that even with HT on based on the overclocks I've seen so far. Maybe reseating the H50 is a good idea as you said, or try different fan configs

Alright - so in my experience, as well as what I'm seeing on overclock.net, most people including myself require 1.4v+ to go beyond 4.6Ghz. The good news is everybody can do 4.5 or 4.6Ghz no problem, but don't be fooled, these chips do start to put out some heat at that speed. My h50, which did an excellent job of keeping my Q9550 at 3.6GHz cool, struggles with my i7-2600k at 4.6GHz. Prime 95 takes me into the mid 70s within 10 minutes. Maybe I just need to reseat my h50, I dunno. I've had 4.8Ghz at 1.45v, but I'm going to have to do something about my cooling first if I want to run that 24/7, much less test it for stability. For cooling, get an h70 or a really good air cooler. I have high hopes that overclockability will improve as new BIOS revisions are released - they're all still somewhat buggy at this point. Regardless, so far I'm quite pleased.Another word of advice (also from experience) - do not populate all 4 RAM slots! My memory, which is rated at 6-8-6-24, will run no tighter than 8-8-8-24 with four modules installed. Surprisingly, 6-8-6-24 vs 8-8-8-24 makes very little difference in MaxxMEM. Either way, I'm able to run it fine at 1.54v - so don't worry about the whole Sandy Bridge 1.5v memory requirement. If you're looking for 8GB of memory for Sandy Bridge, I think I would recommend something like this.Overall, I can't recommend the Gigabyte motherboards enough. I really like my P67A-UD5 now that I've ironed out a couple of the quirks. I don't want to make any blanket statements as to whether or not it's better than the Asus boards, but it does seem that some of the quirks the Asus boards are experiencing are much worse than what I've gone through.As far as FSX, I don't have it fully set up yet, but obviously it is way better than it was with my Q9550. That's all I can say for now. I will have more to come.

Can i ask you how the sb turbo mode handles FSX before you o/c it

Nice, I stay tuned for your tests.I must wait for my new rig with sandy bridge (next week I hope!)Could you do some tests on fps killer sceneries in your FSX ?Did you test FSX without overclocking?

...As far as FSX, I don't have it fully set up yet, but obviously it is way better than it was with my Q9550. That's all I can say for now. I will have more to come....

cmeeks,Thanks for your feedback :Applause: I'd appreciate if you could run the Passmark Peformance test (download here http://www.passmark.com/index.html) and report back your CPU Mark. Make sure to run the test with HT off.Thanks

I moved from an i7 920@4GHz to i5 2500K, currently running at 4.4. It's SILKY smooth for my testing thus far. Definitely a strong improvement! I'm hoping to push the OC further, but I've always been a bit nervous about overclocking. Currently at 1.3V vcore.

Please gentlemen :Praying: Add benchmark results. Passmark Peformance test (download here http://www.passmark.com/index.html) .

3DMark is much cooler and far more relevant to FSX.

Please gentlemen :Praying: Add benchmark results. Passmark Peformance test (download here http://www.passmark.com/index.html) .

Here you are Ulf:

Thanks :Applause: Much appreciated!Exactly what I needed. I asume that you have disabled HT in BIOS since you've OCed to 4.6GHz.