Originally Posted by its my first time
I thought I'd post this for anyone who hasn't come across it, some handy little tips. (Yeah I know it's quite a big post, but worth reading)
Ever wondered why you canâ€™t get past 3.6GHz on that new Phenom II? Some may claim it is a bad chip, but I for one, can guarantee you that is almost always not the case.
I have been overclocking this chip for weeks and studying how it acts while doing so. I may not be an AMD engineer, or an electrical engineer, but here is what I have found:
People always repeat the same/similar phrases about these chips â€œUp the voltage, AMD chips are tanks and can take it!â€ In fact, I have found with the new AM3 Phenom IIâ€™s that it is not always practical to up the voltage past 1.5Vcore if you are just looking for a 24/7 overclock. Before upping Vcore, take into account what else may be causing stability. It could be an unstable NB (IMC) or Ram. I suggest finding the max stable ram and NB clock before OCing the CPU cores.
Also, you may run into your system not booting with more than ~1.475vcore. This is because these new Phenom IIâ€™s actually dislike and do not tolerate high voltages a lot of the time. You are lucky to gain a chip with high leakage, so that you can sustain stability with 1.55V+
A common misconception is that these 45nm Phenom IIâ€™s are using dangerous amounts of voltage for anything past 1.4Vcore. Comon people, these arenâ€™t 45nm Core 2â€™s or Core i7 CPUs. AMDâ€™s 45nm process is completely different, and can maintain higher voltages without any traces of degradation. However, I do not suggest going over 1.55Vcore for a 24/7 air OC.
Last but not least, remember that voltage adds heat to these chips, of which they do not like under high clockspeeds.
The max heat these chips can tolerate without risking damage is 62C. However, instability and crashes can be caused all the way back into the 50-55C range.
Through experience, I, and many others have noticed that these chips LOVE cold. In fact, they scale way better with cold temperatures than adding more voltage to the mix. A great example of this can be seen with some Dry Ice results on these chips:
Take a good hard look at that overclock. 4.6GHz with only 1.408vcore. Simply amazing. Now do you see why voltage is not always the best?
If you plan on air cooling, pick up some nice high CFM fans (as long as you can stand the sound) and a nice heatsink cooler such as the Xigmatek S1283 or a Thermalright Ultra Extreme 120.
3) Multiplier Overclocking
If you are like me, and have a Black Edition cpu, you have probably figured out that overclocking is a piece of cake by just flicking up the multiplier and being done with it. This is not always the case.
I personally recommend against just using the multiplier. Many people have found that using a lower multiplier and a higher HT Ref. Clock can help increase your max overclock+stability slightly.
Not only that, but only using the multiplier will not always net you the best performance. Sure you can hit 4GHz with a 20X multiplier, and a bit more voltage. However, through benchmarking or game performance, you may find it is performing worse than someone elseâ€™s comparable 4GHz using a higher HT Ref Clock. This is because when you up the HT Ref Clock, it also increases ram speed, HT link speed, and NB (IMC) speed. Just remember to watch the stability on each of these.
Here is a direct quote from our very own Chew*:
â€œIm sure some of you may have experienced a crash with cinebenchâ€¦â€¦â€¦sometime you will blue screen, somtimes you will just black screen and sometimes the bench will just crash ( dissapear, etc just shut down ) and windows will still be upâ€¦â€¦â€¦..the blue screen is NB vid/IMC memory related, the black screen is core clocks/cpu voltage related and the just crash/dissapear from desktop is temp relatedâ€¦â€¦â€¦â€¦.â€
Next time you experience a crash, take a good hard look at that for reference. Chew* has more experience than I with these chips, and honestly, he is right about the crashes. I checked myself.
The best method of finding stability on your overclocks is to use Prime 95. Now it is usually debateable for how long you should run a program like this. For the Phenom IIâ€™s however, you need to wait all the way until you can be sure the IMC (NB) is stable. The NB is stressed the most during 512K FFTs. This happens about 2-3 hours into Blend, so I suggest running for at least 3 hours.
Here are a few fixes to common problems:
4GHz stable is not easy with these chips (mostly the quadcore Phenom IIâ€™s). Highly unlikely. In order to achieve 4GHz 100% stable, you need 32-bit windows and you will have to back off memory and NB clocks (maybe even going below stock). However, it would net you greater performance with a 3.8GHz and 2600-2800MHz NB.
If experiencing memory instability, try upping the NB voltage (not CPU-NB VID).
If experiencing overall instability, first check to make sure ram is in check at stock speeds. If that is not the case, try giving the CPU-NB VID +.100 or +.200v.
As a last resort, make sure you have the newest BIOS!
Honestly, I mean it. Mess around with as many settings (even if you think they wonâ€™t change anything) as you can. Every setup is different so experimenting wonâ€™t hurt. There is still more to be discovered about these chips!