DC Computer Solutions: January 2012

DC Computer Solutions - AMD FX-8150 CPU Review

Introduction

There have been a lot of products and inventions through the years that have been misunderstood and not given the credit they deserve. Looking as far back as the invention of the phonograph, even it was looked at as simply a quaint oddity. A parlor toy, if you will. At the time, most people’s exposure to music in the home was singing around their own piano, or simply singing in the shower. Then came the phonograph. It made recording voices and music possible, and with the advent from wax cylinders to reproducible media, it made it distributable. Think about something, at the time of the invention there were no such things as recording artists. Thomas Edison had to create the entire beginnings of the recording industry in order to support his parlor toy. We all see where that has gone….now turn off the iPod and listen to me.

At some point (or points), a product comes along that changes an industry, or in the case of the simple architecture of the phonograph, creates one. In technology, there are constant creations and advances, but oddly, the actual architecture of the CPU hasn’t really changed all that much. The benchmarks we were using ten years ago are, for the most part, still applicable as performance measurements today. This is simply because the way CPUs operate hasn’t changed all that much. But how is this possible in a world of ever changing software looking to grow more complex all the time? At what point does the architecture of the CPU need to change in order to keep up with the software and give the software a chance to grow?
AMD’s new FX-8150 is the first release in their new Bulldozer line, featuring an all new and radically different architecture. The AMD FX-8150 is the first eight core desktop processor to market, but there is much more going on beneath the skin. The eight cores of the FX-8150 are built into four modules on the chip, each with two physical processing cores. These two cores share resources in a way previously unseen, sharing not only L2 cache, but FPUs, as well. This makes for a highly efficient unit capable of incredible multi-threaded capabilities. In addition, the FX-8150 is a Black Edition CPU with an unlocked multiplier. This obviously makes for easier overclocking and the FX-8150 is designed with extreme overclocking headroom in mind. Recently, AMD set a world overclocking record with a Bulldozer CPU with the OC topping out at an astounding 8.4GHz. This, naturally, is not what should be expected from an ordinary home build, but it does show that the FX-8150 has extreme overclocking potential.

Technologies

AMD FX Series Processors

Seamless integration is AMD’s approach as they introduce the latest technology and offer a flexible upgrade path towards the new AMD FX platform. The award winning AMD 6000 series GPUs debuted in Q4 2010, delivering top of the line DirectX11 performance and unparalleled multi-display gaming capabilities to desktop PCs. The 9-series chipset was released soon after, in Q2 2011, laying the groundwork for the AM3+ infrastructure while offering full compatibility with the current crop of AM3 processors. The third part of the puzzle completing the new FX platform is the AMD FX processor itself and it has finally arrived. Unlocked and highly overclockable, these new FX processors feature the world’s first octo-core desktop processor and AMD microarchitecture developed from the ground up. Combined with a 9-series motherboard, the new AM3+ platform supports increased ILDT current for higher frequency HT link up to 5.2 GT/s. The AM3+ socket infrastructure also adds support for CPU voltage load line and increased DRAM current, now supporting up to DDR3-1866. Each 9-series chipset is CrossFireX ready with two PCIe x16 lanes, supporting the latest 6000 series Radeon GPUs, while also natively compatible with NVIDIA’s SLI technology.

The Bulldozer architecture focuses on efficient resource sharing to deliver well-balanced performance and power consumption on multi-threaded applications. Each Bulldozer core is armed with two independent integer clusters each with a dedicated L1 data cache (essentially two physical cores in one Bulldozer core) and modularly, shares L2 cache, Floating Point Scheduler, as well as two 128-bit FPUs supporting up to 256-bit floating point execution. Sharing resources reduces not only the power consumption but also the die space, therefore lowering the cost.

Bulldozer has a deeper pipeline that relies on improved branch prediction and pre-fetchers, aiming to resolve the bottleneck caused by incorrect branch prediction. Unlike the previous architecture, the predict and fetch pipelines are decoupled. A queue of future fetch-addresses is created by the predictor and allows the fetch logic to go through this queue and compare it to what's in the instruction cache. Each Bulldozer module is capable of decoding up to four instructions per cycle, compared to three on AMD Phenom II processors.

Another major change that Bulldozer brings to the table is Power Gating, when paired with a 900-Series Chipset. Each module can be clocked and power gated independently, allowing unused cores to be powered off while the other active cores can be driven up in frequency. This new Turbo Core technology, enhanced for the new FX processors, has a new mode which can run ALL cores for a time in Turbo mode where there is sufficient TDP headroom. There is also a MAX Frequency mode where the FX processor can increase the frequency on half the cores and can remain in a higher frequency state longer compared to previous Phenom II processors, resulting in improved performance in lightly threaded applications.

Built on the latest 32nm silicon on insulator technology, Bulldozer-based chips can have up to 8 cores (each core is seen by the Operating System as a logical processor) comprised of four Bulldozer modules sharing L3 Cache and NB resources between them. Bulldozer is also designed to dynamically switch between shared and dedicated components to maximize efficiency, while featuring new x86 instruction sets, like SSE4.1, SSE4.2, AVX, and XOP including 4-operand FMAC allowing for greater performance and flexibility. These new instruction sets will find use in the next generation of applications that will play a prominent role in the near future. While some new instructions, like SSE, AESNI and AVX, useful for video encoding, data encryption and FP intensive apps, are both supported by the latest Intel and AMD processors, the FX series processors are uniquely capable of processing FMA4 and XOP instructions as well, useful for HPC and numeric applications.

Putting it all Together

The much anticipated launch of Bulldozer has been long coming. There have been small pieces of information available here and there, some confirmed, some merely speculation. One thing that AMD never hesitated to share was that Bulldozer’s Zambezi core was going to be an entirely new architecture, unlike anything we had seen previously. That is certainly the case. Eight cores in four modules, with shared resources in each module for two cores and a boatload of L2 and L3 cache makes for an impressive looking new architecture.
There is also a new approach to the Turbo Core in the FX-8150 and the whole Bulldozer lineup. The FX-8150 sports a stock clock of 3.6GHz. When power headroom allows, all eight cores will ramp up to 3.9GHz under load. That is pretty standard. Where it gets interesting is when only four threads are required. In this case, the FX-8150 will address those four threads with four cores boosted to 4.2GHz provided there is sufficient voltage headroom. That is a big boost with no overclock involved, and the amount of boost can be altered for either state in AOD, should you decide to do so, allowing for what is essentially an overclock when necessary, but a cool running stock chip when the power isn’t needed.
At no point did AMD anoint Bulldozer as a Sandy Bridge killer. Even now, they are quick to point out certain things that it is more capable of, due to its unique architecture, but also are willing to admit where it falls behind a little, due to the same. The question becomes, what are the strong points of this new architecture, and where does it seem to fall short? Another question being, is it the architecture that falls short in some respects, or is it simply more advanced than the software that has perceived lags in?
Breaking down what you are getting into with the AMD FX-8150 is a little more complex due to this. As a result, the platform has enormous strengths and some minor weaknesses. However, the weaknesses seem to be amplified by how well it hits its strengths, but there is no area where you can call Bulldozer an underperformer. Like I said, Bulldozer is a complicated chip in more than its architecture.
We can talk about synthetic benchmarks, and all the GOPS you are getting, or your memory bandwidth, but that really isn’t what most people are looking to know. Most people don’t run Sandra and AIDA benchmarks for entertainment (or work) purposes, so let’s focus on applications you may actually be using, or benchmarks that simulate real world usage. Besides, if you are running Sandra benchmarks for entertainment, you don’t need an explanation here.
The FX-8150 has eight cores….and it likes to use them. During testing the FX-8150 produced some absolutely jaw dropping results in multi-threaded applications. Rendering in Cinebench actually stopped me in my tracks during the test with the speed I saw, and the benchmark numbers certainly back that up. All eight cores worked quickly and efficiently in unison for an incredibly fast 3D render, and the final scores certainly backed that up.
Multi-threaded video applications, such as Handbrake and x264, were absolutely no problem, as the FX-8150 put up outstanding transcoding numbers in both. The FX-8150 split tests in x264 with the Sandy Bridge processors. In Handbrake 0.9.5, the FX-8150 did what really matters – it cleanly transcoded a DVD mpg to mp4 faster than either the 2500K or 2600K at stock speeds, and scaled appropriately faster when overclocked. All in all, the AMD FX-8150 is an incredibly powerful CPU for multimedia creation, and using today’s multi-threaded apps only adds to its power.
In our WinRAR tests, the FX-8150 was able to really shine. This is a multi-threaded productivity app and the FX-8150 took full advantage. Showing that it’s not just an entertainment piece, the FX-8150 put up numbers on par with the 2600K in compression with even better throughput at stock clocks.
Gaming with the FX-8150 is absolutely solid and showed an improvement over the Phenom II and Thuban in almost all cases. Again, the Bulldozer CPU seemed to show an aptitude for more complex and CPU intensive games. Metro 2033 saw almost a 25% performance increase over a Phenom II 980 using the same video card. Real world mimicking benchmarks, like 3DMark 11, saw a huge jump in physics computation, and Unigine and Stone Giant displayed beautiful rendering. One immediately noticeable, but not measured, trait I saw was in S.T.A.L.K.E.R. CoP. It has always been a sticking point that vegetation was seemingly rendered only as you got right on top of it. The FX-8150 rendered the scene significantly further into the distance, making for a much more realistic playing field.
It would seem that the FX-8150 has only one area where it may not meet expectations, and that is with older and single threaded software. Clock for clock, the FX-8150 shows minor improvement over the Phenom II/Thuban, but not the huge leaps we see in multi-threaded apps. Single threaded apps run very capably, but there are no mind boggling numbers, nor are there any performance issues of concern. As I stated previously, it is more of a situation where “runs single threaded apps very well” seems to pale next to its stellar multi-threaded performance. As apps become more complex, the FX-8150 will not only be ready for them, it will be eagerly awaiting them.

Reviewer's Opinion
It’s been a long wait for Bulldozer’s arrival, with the date being pushed back again and again. Naturally, that had me going in looking for the flaw that kept it from coming to market on any of the previous announced release dates. Was the architecture not yet ready? Were there microcode issues? Did they inexplicably catch fire when exposed to lemon meringue pies? Who knows, it was something, and after playing with the chip, my gut hunch is that “something” was a question of the right way to market it.
Bulldozer is new architecture, all new from the ground up. There isn’t another processor out there like it. Usually, there is something on the same page around, but this time there isn’t even anything in the same book store. It’s different and it is incredibly forward thinking. However, with different also comes a different type of performance, and the FX-8150 certainly has anything but traditional performance characteristics. Looking at synthetic benchmarks, they were all over the board in ways that made very little corresponding sense, so it wasn’t until I got to use the processor in actual applications that I got a feel for what it was all about.
The AMD FX-8150 absolutely excels in a multi-threaded environment. It seems the more you throw at it, the better it responds. Look at the WinRAR test, this was always a place that Intel came up big. It uses every available thread, and pushes them. Surprisingly, the FX-8150 absolutely chewed it up and spit it out, posting numbers better than either of its Sandy Bridge competitors. It’s been a long time since AMD has held that distinction.
Multi-threaded video encoding was again a big winner for the FX-8150. It ripped through videos in a flash. The x264 and Handbrake numbers speak for themselves. However, even more impressive was actually sitting with it working in Adobe Premiere. The snappy feeling during editing was outstanding, adding filters on the fly was flawless and when it came time for conversions or transcoding, the FX-8150 whipped through it like nothing. The feeling and speed was drastically different, and for the better.
Gaming was satisfying, and sometimes spectacular. Again, it seemed the more complex the game, the more outstanding the performance became.
With all of these, it was interesting watching Turbo Core work. With a CPU monitor set up, you could see the speed and voltage boosts at appropriate times. Though Turbo Core is not a new idea, the two step Turbo mode is. Only need four threads? Well, four threads at 4.2GHz all being used is much better than eight at 3.6GHz, with four sitting idle. A bit like an instant OC, with flexibility added to allow you to tweak the boost.
Where the FX-8150 doesn’t make improvements in leaps and bounds is in older and/or single threaded applications. It seems curious, but it seems to be a characteristic of the architecture. It doesn’t lose ground here from previous generations, the improvements just aren’t as drastic as they are in multi-threaded apps. I’m sure some are going to throw out the numbers from these and point to them as an issue. But my feeling is this, when was the last time you were typing a letter in Word 2003 and wished your CPU was faster? I am going to guess never. I sure haven’t.
On to the fun stuff….overclocking was a breeze. Like all of the Black Editions I have used, the FX-8150 much preferred a multiplier OC to a Ref Clock boost. 4.9GHz was stable on air, with normal operating temps staying within limits. Only once did it get dicey, and that was on a prolonged eight thread video transcode, and even then temps peaked at 66 centigrade. That may sound a bit hot for an AMD, but we are talking 8 cores, 1.525v under load. It’s going to generate heat, no way around it.
OC performance scaled nicely, though to the naked eye it may not seem as good as it actually is. You need to keep in mind that with stock clocks of 3.6GHz, the Turbo Core allows the CPU to jump to 4.2GHz. So much of the OC when under load is actually a bit smaller than the 1.3GHz you assume.
The AMD FX-8150 is possibly the most advanced processor on the market right now, and brings absolutely stunning performance to the latest and greatest apps out there. Do older apps get the same type of stunning upgrade? Well, no…but software is changing, and you have to make the break somewhere. Trying to be a “one size fits all” really means that “one size doesn’t fit anything correctly”.
The new AMD Bulldozer/Zambezi/Scorpius (call it what you will) architecture is forward thinking. The FX-8150 delivers smoking performance on the latest apps and games and, just as importantly, has the promise to evolve. Right now, it’s time for developers to get the software caught up to the FX-8150’s capabilities. It’s a top performer now and looks to be for some time to come. You can look at all of the out of context benchmarks you like, but in real world use, the AMD FX-8150 is ready to Bulldoze a lot of sand out of its way. If you appreciate the AMD FX-8150 for what it is, and what you are really going to be doing with it, it was worth every second of the wait.
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