Phenom II X4 965 Black Edition ver. 2.0: AMD Introduces C3 Processor Stepping

AMD promises that processors on Deneb core with the new C3 stepping will offer lower heat dissipation, improved overclocking potential and a few other enhancements. But will this make Phenom II X4 processors more attractive?

by Ilya Gavrichenkov
11/03/2009 | 09:11 PM

The introduction of 45 nm manufacturing process allowed AMD to increase the clock speeds of their processors very rapidly. The top Phenom II X4 CPU works at 3.4 GHz frequency and it is even higher than the maximum clock speed of the top desktop Intel processors. However, clock frequency is no longer of the same significance as it used to be before. That is why Phenom II X4 CPUs working at such high speeds yields quite noticeably to Intel processors from the high price range. Partially the blame is on not the most progressive Stars (K10) microarchitecture used in AMD products. As we have already shown in our previous reviews, the clock frequencies of contemporary Phenom II processors should be way higher than where they are right now in order for them to compete successfully against Intel Nehalem CPUs. However, this is almost impossible and the recently announced Phenom II X4 965 processor with 3.4 GHz clock frequency and 140 W maximum TDP (which is extremely high for desktop CPUs) proves it. Having analyzed the specifications of this processor we concluded that this model will remain the fastest Phenom II solution until principally new cores come into play.

 

AMD, however, doesn’t feel like giving in yet. They believe that Stars (K10) microarchitecture and 45 nm manufacturing technology still have some potential. Today the company is launching the refreshed Phenom II X4 965 with 15 W lower maximum TDP of 125 W, which is more acceptable from the consumer standpoint. They managed to accomplish that due to the new Deneb processor stepping with improved thermal and electrical specifications and a number of other enhancements. Our today’s review will be devoted to this particular new Phenom II X4 965 processor.

Closer Look at Phenom II X4 965 Black Edition

So far the new Deneb processor stepping marked as C3 didn’t allow AMD to raise the clock frequencies of their processor lineup. Therefore, AMD refrained from launching the new CPUs and decided to introduce the new core into the already existing processor models first. Especially since the lowering of the top processor model thermal design power by 15 W is a definite improvement that will inevitably increase the attractiveness of this CPU model.

So, there will be two versions of Phenom II X4 965 processors with different cores: with 140 W and 125 W heat dissipation. Moreover, in terms of formal specs there are no other differences between them. Both CPUs even belong to the same Black Edition series that implies an unlocked multiplier. Nevertheless, processors with different stepping will have appropriate marking that will help distinguish between the solutions with different TDP. For example, CPUs based on C3 Deneb core will be marked as HDX965FBK4DGM, while Phenom II X4 965 processors with an old core will have the marking HDX965FBK4DGI. In other words, you can tell the processor stepping by the last symbol in the marking.

The new Phenom II X4 965 has the following specifications:

I have to say that besides lowering the maximum thermal design power, they have also changed the electrical characteristics of the new processor. While Phenom II X4 965 on the old core had a maximum nominal Vcore of 1.45 V, the new processor stepping has lower maximum Vcore of 1.4 V. All this suggests that the introduction of the new more economical processor stepping may also increase the frequency potential of the new processors revealed during overclocking.

The diagnostic CPU-Z utility has no problems identifying Phenom II X4 965 with the new C3 stepping. The screenshot below shows very well that the new CPU supports slightly lower core voltage:

I would like to stress that the improved specifications of Phenom II X4 965 processor will not affect their price. Just like their predecessors on the old core, the newcomers will be officially sold at $195. However, it doesn’t mean that the CPUs on the new core will quickly oust their predecessors from the market. AMD is going to ship both types of Phenom II X4 965 simultaneously and this will go on at least until March 2010. Therefore, if you are not looking specifically for the CPU on the new core, then you should pay attention to the processor markings.

Innovations in C3 Processor Stepping

The new C3 stepping of the Deneb processor core will eventually come to other Phenom II CPUs, besides the top models. However, only the new processor stepping will bring lower TDP only to the Phenom II X4 965 CPUs. This can be regarded as indirect indication that C3 processor stepping doesn’t provide too much of improvement in electrical and thermal characteristics.

We measured the practical power consumption of the old and new Phenom II X4 965 and it clearly indicates that:

In this case we measured the power consumption along the 12 V power line connected to the CPU voltage regulator, which means that the numbers above include the power losses that occur in the mainboard voltage regulator too. Nevertheless, they are quite sufficient for comparative purposes. The processor temperatures in the table above was taken off the diodes inside the processor cores. We used Thermalright Ultra-120 Extreme processor cooler with Enermax Magma fan. The processor was loaded using LinX 0.6.3 utility. Cool’n’Quiet and C1E power-saving technologies were activated.

The obtained results show that under maximum workload the new Phenom II X4 965 processor with C3 stepping proves only 7-8 W more economical than the C2 processor stepping. And it is only half the difference between their calculated TDPs. In other words, we shouldn’t overestimate the role of the processor stepping in the practical heat dissipation and power consumption. At the same time we should note that a Phenom II X4 965 processor on the Old core we had in our lab is not so bad at all in terms of power consumption. Its nominal core voltage is 1.4 V, just like the core voltage of the new CPU sample we got for review. However, Phenom II X4 965 processors with C2 stepping and 1.45 V Vcore may show considerably higher practical power consumption.

Lower power consumption and heat dissipation are not the only improvements AMD engineers introduced in the new Deneb C3 processor stepping. They have also done some work on the memory controller integrated into the CPU, as it now has improved electrical stability when working with four modules. In reality it means that if there is proper support in the mainboard BIOS then the processors with the new stepping can work perfectly fine with four DDR3-1333 SDRAM modules. As for CPUs with C2 processor stepping, then could only work stably with four DDR3-1067 SDRAM modules, while faster memory could only be used in dual-module configurations.

The third improvement introduced into the new processor stepping deals with the way C1E power-saving technology works. As you know, this power-saving technology allows lowering the CPU frequency and core voltage in idle mode upon the command from the OS. Until now AMD processors didn’t have any hardware implementation of this feature and C1E work was emulated via Cool’n’Quiet technology. However, this algorithm first required special support in the mainboard BIOS, and second was pretty awkwardly implemented causing the performance to drop as soon as it got activated. Processors with C3 stepping have finally acquired hardware implementation of C1E technology. AMD engineers promise that now C1E can be activated without risking to experience any performance drops, because the transition into this mode and back occur very rapidly.

In reality things turn out not so rosy. The thing is that activation of C1E technology on Socket AM3 platform requires Cool’n’Quiet to also be enabled at least in the existing versions of the mainboards BIOS’s. Therefore, we can’t really appreciate the advantages of the C1E hardware implementation in the new Deneb core to the full extent. Cool’n’Quiet technology either with C1E or without it continues to lower the performance of AMD processors by about 3-5% independent of the processor stepping type.

To illustrate what we have just said we can offer you the results of SYSmark 2007 that emulates the user’s work in different real applications:

Therefore, at this point we can advise the owners of systems built around Phenom II processors only to disable Cool’n’Quiet technology and sacrifice the power-saving in idle mode if they want to achieve maximum performance levels. However, it is also important to point out that the performance doesn’t drop too much when the power-saving technologies are in fact active.

As for the “pure” CPU performance, it hasn’t changed with the introduction of the new processor stepping. C3 stepping of the Deneb core has no microarchitectural improvements that could increase Phenom II X4 performance to a new level.

Overclocking

The primary advantage of the new processor stepping – lower heat dissipation – should in fact tell on the frequency potential growth. To check this assumption we performed a few traditional overclocking experiments. We used a system built around Gigabyte MA790FXT-UD5P mainboard and used a Thermalright Ultra-120 Extreme processor air cooler with an Enermax Magma fan installed on it.

Since Phenom II X4 965 processor we are talking about today belongs to the Black Edition series we decided to overclock it in the most natural way in this particular situation: by raising its clock frequency multiplier. At the same time I would like to remind you that as we have already seen many times before, the alternative approach using increased clock generator frequency is just as efficient.

Speaking of the overclocking results I would like to say that the CPU with new processor stepping did in fact demonstrate higher frequency potential. I would like to remind you that during the first Phenom II X4 965 C2 processor stepping tests we could get the CPU to work stably only when we increased its clock frequency from the default 3.4 to 3.8 GHz. With the new Phenom II X4 965 the overclocking maximum with an air cooler was immediately increased by 200 MHz.

When we increased the CPU Vcore by 0.175 V above the nominal value, our test processor achieved stability at 4.0 GHz clock.

At the same time we managed to increase the frequency of the North Bridge built into the processor to 2.4 GHz. We also had to increase the corresponding voltage by 0.075 V.

It is a highly positive thing that Phenom II X4 965 processor managed to hit 4.0 GHz bar during overclocking. It indicates that the new core can not only lower the heat dissipation of the top model in the AMD quad-core lineup. Its increased frequency potential may allow the manufacturer to design an even faster solution than Phenom II X4 965. However, at this point there is no credible information that a Phenom II X4 975 will ever come out.

Testbed and Methods

We have already discussed the performance of the Phenom II X4 965 processor with previous stepping. Keeping in mind that the new processor stepping doesn’t have any microarchitectural improvements it doesn’t make much sense to test the performance of another similar CPU one more time. Nevertheless, since the new Phenom II X4 965 managed to overclock to the psychologically important 4.0 GHz barrier, we decided to compare the performance of this overclocked processor against the performance of other overclocked processors with comparable price tags. This test session will allow us to conclude which of the existing mainstream quad-core CPUs will be the best fit for an overclocker platform.

We are going to compare Phenom II X4 965 against two Intel solutions with similar price point: Core 2 Quad Q9400 and Core i5-750. This way, we ended up using three major testbeds during our test session:

  1. Socket AM3 platform:
  2. LGA775 platform:
  3. LGA1156 platform:

Besides the above mentioned components all testbeds also included the following:

The parameters of tested processors in their nominal mode and during overclocking are summed up in the table below:

Performance

General Performance

Phenom II X4 965 is a pretty contemporary high-performance processor. With the introduction of 45 nm production process AMD managed to make sure that their processors could finally compete against Intel solutions for LGA775 platform. In nominal mode Phenom II X4 965 performs way better than Core 2 Quad Q9400 with the same price. However, 18% overclocking to 4.0 GHz is not enough for AMD solution to outperform the overclocked LGA775 processor. The thing is that Core 2 Quad has a much better overclocking potential in relative prospective. Even during overclocking to 3.84 GHz limited by the mainboard’s ability to increase the FSB frequency, the clock speed of Core 2 Quad Q9400 processor gets 44% higher. It is more than enough for this processor to look much more convincing than its overclocked Socket AM3 competitor in most cases. As for the LGA1156 platform, the results suggest that it is one of the new generation solutions with a completely different level of performance. Even in the nominal mode Core i5-750 shows results which are just a little lower than the performance of the overclocked Phenom II X4 965. However, once its frequency reaches 4.0 GHz, which is in fact not the maximum this CPU is capable of, the performance of Core i5-750 becomes unattainable for the previous generation CPUs.

Gaming Performance

The results indicate that the new LGA1156 Lynnfield processors boast the best gaming potential among all tested mainstream solutions. It even comes to the point when Core i5-750 processor working in nominal mode (with enabled Turbo Boost technology) easily outpaces Phenom II X4 965 processor overclocked to 4.0 GHz. Unfortunately, this is pretty sad for AMD proving one more time that Stars (K10) microarchitecture is inevitably becoming outdated.

The new AMD flagship solution doesn’t look too good against the Core 2 Quad Q9400 either. Overclocking allows this LGA775 processor to leave behind the system with Phenom II X4 965 overclocked to its maximum. The new AMD CPUs can perform relatively well against its competitors only in nominal mode. However, even here Phenom II X4 965 outperforms only Core 2 Quad Q9400, which is one of the previous generation solutions, which are now being replaced with the new faster LGA1156 processors.

Performance during Video Transcoding

Video transcoding is one of the few tasks where contemporary AMD processors show their real power.  In nominal mode Phenom II X4 965 is far ahead of Core 2 Quad Q9400 and is almost as fast as Core i5-750. However, since Intel processors have higher relative overclocking potential, the Core i5-750 working at 4 GHz frequency runs considerably faster than the AMD solution overclocked to the same level. But the LGA775 CPU can’t boast the same success: despite the fact that its frequency increases more during overclocking than that of the Phenom II X4 965, the AMD solutions till performs better during video transcoding.

Performance in Applications

When we compare the results of our overclocked testing participants in Photoshop, the conclusions are not so positive: Phenom II X4 965 is the slowest 200-dollar overclocker CPU for this type of tasks among all existing choices.

We can draw the same conclusion when we check out the results obtained during final rendering tests in 3ds max 2010. Phenom II X4 965 may seem like an interesting solution only when we compare the processor performance in nominal mode. Although in this case we should also disregard the results of LGA1156 platform, which is faster no matter what.

There is nothing new we could say About Phenom II X4 965 performance in Mathematica 7 suite, too. Unfortunately, even the promising looking overclocking of our Phenom II X4 965 processor to 4.0 GHz cannot compete against Intel based platforms that offer way higher performance in many real applications.

Power Consumption

We would like to wind up our today’s review of AMD Phenom II X4 965 processor on Deneb core with C3 processor stepping with the power consumption tests. As we have already demonstrated, the power consumption of this CPU in nominal mode is not very different from the power consumption of the similar processor on the previous core stepping. And it means that the new Phenom II X4 965 won’t compare against Intel solutions in energy efficiency. However, since we are focusing mostly on overclocking in our today’s review, we should also check what power consumption readings we can take off the 200-dollar CPUs during work beyond the nominal mode.

The following numbers show the total power consumption of the tested platforms (without the monitor). During our tests we used 64-bit LinX 0.6.3 utility to load the systems to the utmost extent. Moreover, to ensure that we estimate the power consumption in idle mode correctly we activated all power-saving technologies, such as C1E, Cool'nQuiet 3.0 and Enhanced Intel SpeedStep. However, I have to say that during overclocking only LGA1156 platform has all power-saving technologies intact. Other two platforms do not let overclocked processors to lower their core voltage in idle mode if it has been increased during overclocking.

Here I only have to say that during overclocking we increased the core voltage of both Intel CPUs to 1.4 V and that of the AMD processor – to 1.575 V.

When there is no tangible load in place the difference in practical platform power consumption becomes very noticeable. The most economical is Core i5-750 that can switch to fully-fledged energy-efficient states even after overclocking with Vcore increase. The power consumption of Socket AM3 platform with the installed Phenom II X4 965 CPU on new processor stepping is beyond any criticism: overclocking increases its power consumption quite seriously, which makes it consume in idle mode just as much as other mainstream platforms would under heavy operational load.

And although during overclocking to 4.0 GHz the maximum power consumption of Phenom II X4 doesn’t increase as much as the peak power consumption of systems on overclocked Intel CPUs, it still remains the least economical overclocker solution.

To get a better picture of the situation we also tested the power consumption of our testing participants under heavy load without taking into account the rest of the system components. To be more exact, we measured the power consumption along the 12 V power line connected directly to the processor voltage regulator on the mainboard and along the mainboard power lines.

High power consumption of the AMD processor is no longer a secret to anyone that is why we first of all wanted to draw your attention to the relative increase in power consumption of any overclocked CPUs. Overclocking raises the energy appetites of processors, which you should definitely keep in mind when shopping for power supply units and CPU coolers. For example, 50% overclocking of Intel processors results in almost doubling of their power consumption. With Phenom II X4 things are a little better: at 4.0 GHz frequency this processor consumes “only” 75% more than the same CPU at 3.4 GHz. Nevertheless, in absolute numbers its power consumption reaches shocking 250 W.

In addition we also measured the mainboards power consumption. The thing is that LGA1156 and LGA775 platforms use the power sent to the board along the 12 V power line for the processor cores. Uncore part of the CPU and the memory are powered from the mainboard via 24-pin ATX power connector. That is why the mainboards power consumption is worth checking out.

However, the revealed results can hardly change anything in the shaped up general picture. The mainboards power consumption doesn’t increase significantly during CPU overclocking, even on LGA775 or LGA1156 platforms. As for Socket AM3 mainboard, it consumes practically the same amount of power in nominal mode and during CPU overclocking.

Conclusion

Strictly speaking, the launch of the new Deneb processor stepping can hardly be considered a milestone event. As our tests showed, the new C3 stepping brought minor changes to the Phenom II X4 processors. Among them are: slight reduction in the power consumption and heat dissipation, about 200 MHz increase in the overclocking potential and higher stability in configurations with four memory modules. Therefore, we should mostly talk about a cosmetic refresh of the Deneb core and not about some radical progress. However, it is not so bad for AMD, who have already squeezed everything they could out of the old microarchitecture and 45 nm process. At least now the company and its fans can hope to soon see Phenom II CPUs with higher clock speeds than the current top of 3.4 GHz.

As for the new AMD Phenom II X4 965 processors on the new core stepping introduced today we can certainly recommend them to those computer enthusiasts that have good reasons to go with Socket AM2/AM3 platform. The CPUs with new processor stepping will definitely be better than their predecessors. However, it is important to remember that top quad-core AMD processors are currently a pretty weak offering against the background of their competitors. In fact, they can only compete against the old similarly priced LGA775 CPUs and only in terms of nominal mode performance.

In other words, the launch of the new Intel LGA1156 platform made it difficult for AMD to get not only into the upper but also into a significant part of the mainstream price segment. And no new processor stepping can change this state of things. Therefore, we can only expect AMD solutions to return to high-performance segment only when they move their upcoming CPUs on Bulldozer microarchitecture to mass production. Unfortunately, it can happen only in 2011 at best.