How to hit the sweet spot oc'ing the Phenom 965?
Ok so my question is this. It is very easy for me to use AMD overdrive to get my 965 to 4ghz no problem just by simply upping the multiplier. However performance does not seem to increase much. Alot of guides that I have read here advise that to oc these things well all you should do is up the multi. However I have read in several other guides that you will get much better performance by finding the balance between upping the multiplier, HT. REF clock, and the PCIe speed. Other guides on here say not to even mess with these. I believe by increasing these other factors it would seem to balance out the cpu clock per clock because it would increase performnce in other aspects as well. I am quite confused should I mess with the ref clock and PCIe speeds? Wouldnt that give me more performance than simply upping the multi? I would appreciate any comments about experience on this matter a I am trying to achieve the best possible OC. Thanx folks
When you use only the multi, you get to isolate the CPU speed from other components. Reference clock (stock 200) effects the Northbridge, HT Link, and memory, as those 3 components final speed is determined by Ref* their own multiplier. If you are leaving the voltage on auto, your motherboard will most likely feed more volts than the CPU needs. It is highly recommended that you control the voltage manually.
On that note, all settings which are on auto in the bios should be taken off auto and set manually to their stock levels (memory timings+multi+volts, NB, HT, CPU voltages) as the auto settings will allow the motherboard to change things it sees fit. This is most important for the memory timings. This eliminate variables that would otherwise be out of your control, invalidating testing methodology.
A common way to OC BE chips is to use the multiplier at first until a max stable multiplier is found upping volts only as needed and by the smallest amounts. Then from there, upping the Reference clock until stability dissappoears, again, upping volts only as needed.
AMD chips benefit substantially from Overclocking the NB, but this should be left until after you have stabilized everything else.
Ok thank you for your reply it is very helpful I just have one more question. When I leave everythign in my bios set to auto but i only use AMD overdrive to overclock does my mobo still adjust the voltage on its own?? Or does it only adjust those variables on its own when I use the Bios to overclock? I have wondered this for quite some time. I know overdrive is not as stable as bios I just really like using it for some reason it seems so much more "fun" to me. Lol. IDK why.
Ya my gigabyte board auto adjusted voltages on its own extremely well barely ever going over what was needed. Now that I got this new Asus 890gx board this thing sets voltages to ludacris levels!!! Lol. I tried to keep everything auto to see how smart the board would be and I will never make that mistake again!!! I Oc'ed just the cpu (965be c3 stepping) and it set the volts from stock 1.4 to a furnace boiling 1.53 volts! I get 4.2ghz stable manually from that on this board. Not only that I was wondering why my cpu temps were idling at 45 celcius with a corsair H50 in push/pull. I was like WTF I never get temps that high with this cooler? it was because it set the NB voltage to a whopping 4.5 volts and did the same for mt CPU/NB voltage as well!! All I can say is never trust an Asus board to auto set ur voltages unless u wanna kill all ur components lol.