Recently I have decided to begin overclocking again. With little effort I reached 3.4Ghz and struggled to reach 3.6Ghz. Here are my tests:
I calculated I would need to increase my voltage about 0.02083v/100MHz STEP by:
@ 3.6GHz voltage = 1.475v @ stock speed voltage = 1.35v
1.475v-1.35v = 0.125v
0.125v/6 = 0.02083v (6 because 6 100MHz STEPS)
@3.7GHz the voltage should be near: (1.35v + (0.02083v * 7)) = 1.48581v
@3.8GHz the voltage should be near: (1.35v + (0.02083v * 8)) = 1.516v
Am I doing something wrong that I am not aware of that limits my speed?
At 3.6Ghz I reach 60C when the max CPU temp is listed by AMD as 62C ... would this be a reason I cannot stay stable at a higher speed?
Does anyone have an AMD Phenom II 940 and an ASUS Crosshair II Formula and have this problem?
Well my main question here is why cannot I get past 3.6GHz?
Processor: AMD Phenom(tm) II X4 940 Processor (4 CPUs)
I see a couple of things that could be limiting factors for your OC. The first is running W7 64-bit, which for most seems to shave about a 100MHz right off top, from what I have heard others say. The second is 8 Gig of memory. Just being able to Boot with 4 sticks populating all the slots is a feat-in-of-it self for some (added stress for the on-chip memory controller). Double check to see that your memory voltage is set to spec. You may need to scale up a tad to get it stable at higher clock speeds (this may void any warranty).
Or it might just be as simple as the system not liking a Multiplier setting higher than 18x. My 940 didn't like anything over 18.5x, but I was able to up the FSB (Bus speed) to @207, for an OC speed of @3830. Keep in mind that when you start upping the FSB that this is also OC'ing most of the other components of your system (ie...memory, harddrives, etc..)
As far as the HT speed not staying set, the only thing I can think of off the top of my head is that maybe you didn't up the Processor-NB Frequency Multiplier. Because the CPU-NB HT Link speed cannot exceed the Processor-NB Frequency multiplier by default.
That was some very good information, thank you unclefester. But My HT is still not where i set it to. The NB reads the correct setting of 2.2GHz where my HT reads 1.8GHz.
Also my speeds vary a lot. My CPU goes from 2.9GHz to 3.6Ghz. Is there a setting that allows the computer to change the clock speeds automatically besides cool and quiet and C1E support (I disabled them both)
I have a Phenom II 940, bought it about a year ago when AM3 launched and the 955/945 launched dropping the price of a 940. I need 1.45V to be stable at 3.6, never got anything stable above that. When these were launched 3.8Ghz was a good overclock, a number of users had trouble getting past 3.6 without insane voltage.