AMD Phenom II X4 965BE Rev C3


Overclocking - The road to 4.00GHz
Our journey commences with the following variables:
HTT Base Frequency: 200MHz
CPU Multiplier: 17x
CPU Voltage: 1.4000V
Northbridge Multiplier: 10x (2000MHz)
HT Link Frequency: 2000MHz
DRAM Frequency: 1333MHz
Overall Clockspeed: 3400MHz
Our particular AMD Phenom II X4 965BE had defaulted to 1.400V. We were a little perplexed by this given that the processor is meant to have a TDP of 125W, which typically means a CPU voltage of 1.3500V to 1.3750V with an AMD Phenom II processor. For our own interest we "undervolted" the processor to 1.3500V and was able to run stability tests all day long. To make things a little more juicy we kept the processor at this voltage while overclocking.
We started by raising the CPU Mutiplier in 0.5x increments and for each clock speed increase, OCCT's CPU Test was ran for 5 minutes to detect any horrific levels of instability. The process was smooth until our system restarted after a more extensive stability testing session at 3.80GHz. A 400MHz overclock at less than stock speeds? Not too shabby. A voltage of 1.400V was required to run the OCCT Linpack test stable for the whole hour duration.
After a 0.0500V increase to 1.4000V, we had successfully met the 4.00GHz barrier. Sadly, it took less than 30 seconds of OCCT's Linpack test for the system to reboot.
After minor adjustments to the CPU Multiplier, Base HTT Frequency and CPU Voltage, we attained a maximum frequency of 3.940GHz with an effective 1.5250V applied in BIOS. All in all, a 60MHz decrement and a 0.1000V Voltage increase from 4.00GHz was commanded for a stable overclock. This may well be a new stepping but the typical Overclock Wall strikes again. The overclock however was completely stable and following an hour of OCCT Linpack, it was able to run Prime95's Blend test for a further three hours before we halted the test. This by all intents and purposes is a stable setup for the typical user however it's open to debate as to how much stability testing is truly required as it'll depend on the system's usage. If for example, the processor is working flat out running distributed computing projects such as [email protected] then one would want to be running stability tests for a far longer period of time, but then again this doesn't constitute normal system activity.
Further increases in CPU Voltages would raise it's temperatures past sensible margins and so it was decided to open a window, taking ambient temperatures to a chillier 15c. After trying different combinations of CPU HTT and CPU Multi, incremented Northbridge and HT Link Voltages as well as adjusted Advanced Clock Calibration (which shouldn't even help for this processor), this particular Deneb had no more to offer. We were however also able to increase the processor's memory controller frequency from it's default 2000MHz to 2424MHz.
So all in all our final Overclock stands at
HTT Base Frequency: 202MHz
CPU Multiplier: 19.5x
CPU Voltage: 1.5250V (1.504V Effective)
Northbridge Multiplier: 12x (2424MHz)
HT Link Frequency: 2020MHz
DRAM Frequency: 1333MHz
Overall Clockspeed: 3939MHz
It remains to be seen whether the Rev C3's memory controller is less irritable when overclocking on a 32bit operating system, like the previous Rev C2 processors but it's quite possible that we could have clinched 4.00GHz stable in Windows XP or Vista 32bit. That being said, we care more for overall system stability .
Let's continue to the testing phase to see how speedy this processor is and how much of an impact the overclock makes.
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Most Recent Comments

15-11-2009, 11:35:55

Great stuff.

Thing interesting me is what market is open for these AMD cpus.

I feel they need to provide a 'need' to buy an AMD cpu. Existing AM2/3 owners will see them as attractive, but this market I think is both small and arguably only getting smaller.

If u have even an existing 775 setup, do u switch ? (similar argument to changing to anything - age of components maybe)

If ur older setup craps out, do u go AM2/3 or iX/775 ?

Without being an immediate 'got to get' I think it's too easy to overlook them. I can think of 100s of people who recognize these, and previous AMD models, are damn fine cpus - very respectable, and yet when the crunch comes they still won't go AMD<-Intel.

They need something. I've been a long advocate of them doing something special between their cpus and gpus. Something special that if u have 1 of the group, u can't experience, yet coupled together u get.... something.... They've got both techs in their labs for years now, it's about time they pushed something unique.Quote

15-11-2009, 11:53:35

It would be something to see some kind of "synergy" between their CPU's and GPU's though we'll see how something like that could be implemented beyond just hot air from the marketing department.

As it stands, AMD is playing the "bang per buck" game however this has diminished with the arrival of the Core i5 750. The 965BE and i5 750 exchange punches on the gaming front but it's all over when we start factoring in overclocking headroom.

While overclocking yields have improved (as shown) it still has nothing on the Core i5/i7 processors which (heatsink allowing) tends to have little trouble reaching 4.0GHz. AMD are also able to tout good results with their system platform as they already have a strong graphics card and right now, much of today's games seem to have enough GPU dependancy for the CPU to take a back seat (within reason of course).

This competitive bang per buck edge will diminish to some extent over the next year, although their Thuban 6 core CPU will help gain some more sales. Unfortunately for AMD, they will have to let Intel pound ahead in the upper high end until Bulldozer is alive and kicking.Quote

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