AMD FX-8150 CPU Overclocking Review: A Bulldozer for Gamers?

[siopao1984]

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AMD FX-8150 CPU Overclocking Review: A Bulldozer for Gamers? by VR-Zone.com

Zambezi is the fourth-longest river in Africa (the one with the beautiful Victoria Falls), and also the codename for the new FX series of "Bulldozer" desktop enthusiast CPUs from AMD. After months of speculation and spin about the launch date and performance numbers, the new processors have finally hit the shops and we bring you our review of the top of the line FX-8150.

Overview of the AMD FX Platform



First, to set your expectations right from the start, this is a chart/bombshell from the reviewer's guide itself:



As we can see, despite the hype from previously leaked marketing slides and forum trolls claiming otherwise, today's AMD FX series of processors are NOT designed to go head to head with Intel's higher end SKUs like the i7 2600k or the 6-core i7 "Gulftown" 990X. This is evident in the performance tests in the later pages of our review.

These are the products launching today:



Suggested retail pricing is US$245 for the FX-8150, US$205 for the FX-8120, US$165 for the FX-6100 and US$115 for the FX-4100. At this point of time it is not known or tested if the 4/6-core models have disabled core unlock capabilities.

The new AMD FX models are on AM3+ (942 pins) socket, which retains mechanical compatibility with older AM3 motherboards, provided they can supply enough peak current and receive a BIOS update from the respective vendors to support the new processors. Officially, AMD recommends the use of the 990FX/990x/970 + SB950 chipsets, but we've seen motherboard vendors tout that the new processors will work from mature models like 760G to the more modern 890FX.

Platform Specifications/Die Shot:





Much have been said about the new Bulldozer architecture on VR-Zone and other websites already so we will write more in detail about it in a later article this week. For now, we move on to what our readers will be most interested in: overclocking and benchmarks...

[siopao1984]

AMD FX-8150 CPU Overclocking Review: A Bulldozer for Gamers? by VR-Zone.com

Zambezi is the fourth-longest river in Africa (the one with the beautiful Victoria Falls), and also the codename for the new FX series of "Bulldozer" desktop enthusiast CPUs from AMD. After months of speculation and spin about the launch date and performance numbers, the new processors have finally hit the shops and we bring you our review of the top of the line FX-8150.

Test Setup / Methodology

The 990FX motherboard that we will be using today is ASUS's top of the line Republic of Gamers Crosshair V Formula which we reviewed earlier this year.

• CPU: AMD FX-8150 8-core/8 thread processor (3.6GHz to 4.2GHz, Turbo and C&Q/C1/C6 states on)
• Motherboard: ASUS ROG Crosshair V Formula (BETA 9905 bios made by Shamino - with latest BD AGESA, also unlocks higher memory multipliers)
• RAMs: 2 x 4GB G.Skills RipJawsX 1600Mhz 9-9-9-28 1T (memory frequency/timings investigation later today)
• Graphics: AMD Radeon 6990 (Crossfire) with Catalyst 11.10 Preview 2 (8.901.2.0)
• HSF: Thermalright Silver Arrow with 2 Fans
• SSD: Corsair X128 SSD
• PSU: CM Silent Pro M 1000W
• OS: Windows 7 x64 with SP1

Going up against the FX-8150 is a 4-core/8-thread Intel i7-2600K running on a ASUS Maximus IV Extreme with other identical control components. Instead of using the 4 core/4-thread i5-2500K, we decided that it would only make sense to pair a 8-threaded processor against a 8-threaded processor. Using the AMD Radeon 6990 also ensures that any graphical bottlenecks would be taken care of.

Overclocking/Temperatures & Diatribe:

The only logical reason why anybody would buy a top of the range unlocked multiplier processor would be to overclock it - so we did.



Despite our best efforts, we could only push our FX-8150 sample to 4.7GHz on Air (CPU-Z Validation Link). This was done by applying the "Extreme OC" preset on the motherboard for overclocking timings and secondary voltages, applying a 23.5x multiplier and manually setting the CPU voltage to 1.47v. At this voltage, temperatures were around 70 degrees celcius on full load (Prime95 Large FFTs). Your actual mileage may vary, but according to AMD engineers the typical Air Cooling setup will achieve ~4.6GHz with all cores/modules enabled. The good news is that there is no "cold bug" at sub-zero temperatures, and LN2/phase change overclockers have been running this at higher frequencies.

The Intel i7-2600K setup was also set to 4.7GHz (lowered from 5.2GHz) and 1.47v for "clock for clock" comparison sake.

Since we're not chasing world records, we tested our overclocks over many hours of Prime95 Blend and Linpack to stress the CPU/Memory subsystem. Some other hardware sites and ignorant end-users seem to always show improbable overclocks which have no other utilitarian use other than to boot into windows and take a CPU-Z screenshot or maybe run a few (borderline stable) benchmarks. Worse still is the practice of "disabling cores" to achieve higher clocks, which is just blatent misrepresentation and counter-productive.

In the UEFI bios, we also set:

• CPU-NB Frequency set to 2400MHz from 2200MHz and left the HT Link Speed at Auto (2600MHz). We played around with the voltages but failed to go any higher.
• Used the 1600MHz memory strap. We will cover memory frequency/latency scaling in a later article.
• Disabled APM (application power management, induces clock throttling when TDP limits are hit)
• Enabled HPC (High Performance Computing, not sure what it does exactly but we see marginally higher scores across the board with it turned on)
• CPU/Chipset/Memory power regulation settings set to their most aggressive

Cool & Quiet, C1 state, C6 state and other power saving options were turned off during overclocking - we really can't fathom why anybody will choose to turn them on as they have been proven to induce:

• framerate jitter in games
• latency problems for audio/video applications
• reduced storage performance
• stability problems when overclocking/resuming from standby

Moreover, the power savings from turning these features on is almost negligible, especially on a 125W TDP CPU (and presumably paired with a power hungry GPU as well).

Ecomentalists who pay a premium for "Green" edition mechanical harddrives are also suckers, as they save an insignificant amount of power but have to live with crippled performance and annoying spin-up/spin-down head wear.

[siopao1984]

CPU - AIDA64 Cache/Memory Benchmark

AMD FX-8150 @ Stock Settings



Intel i7-2600K @ Stock Settings:



Straight away, we see glaring differences in the memory/cache bandwidth and latencies with the Intel chip winning by embarassing margins even with the 500Mhz clock disadvantage. Let us put them clock for clock @ 4.7GHz:

AMD FX-8150 @ 4.7GHz



Intel i7-2600K @ 4.7GHz:



The story does not change much here either when the clocks are matched at 4.7GHz.

[siopao1984]

CPU - Nuclearus Multi Core

Nuclearus Multi Core allows us to measure ALU, FPU and Multithreaded Performance on a variety of basic mathematical operations.

AMD FX-8150 @ Stock:



Intel i7-2600K @ Stock:



The FX-8150 does pick up some small individual wins owing to its strong FP performance but still yields overall to the i7-2600K.

AMD FX-8150 @ 4.7GHz:



Intel i7-2600K @ 4.7GHz:



Surprisingly, Intel's margin of victory in the overclocked test decreases during overclocked clock for clock comparison, but AMD is still some way behind. This could mean that if both chips kept scaling with frequency, the AMD just might overtake the Intel at some point (probably beyond practical cooling and voltages).

[siopao1984]

CPU - Fritz Chess Benchmark

AMD FX-8150 @ Stock:



Intel i7-2600K @ Stock:



AMD FX-8150 @ 4.7GHz:



Intel i7-2600K @ 4.7GHz:



Not much better news for AMD here either - it's 22% slower at stock and 17.7% slower clock for clock. Another case where the gap seems to be closing when the frequency scales up.


CPU - wPrime (8 threads)

AMD FX-8150 @ Stock:



Intel i7-2600K @ Stock:



AMD FX-8150 @ 4.7GHz:



Intel i7-2600K @ 4.7GHz:



Again, Intel takes the lead in this floating point and latency sensitive benchmark.

[siopao1984]

CPU - Cinebench R11.529

AMD FX-8150 @ Stock:



Intel i7-2600K @ Stock:



AMD FX-8150 @ 4.7GHz:



Intel i7-2600K @ 4.7GHz:



Cinebench R11.5 is quite a good gauge for single threaded and multithreaded performance. We will be using these figures in our performance/price and performance/watt tests later.

[siopao1984]

CPU - x264 HD Benchmark 4.0 (video encoding)

We took the precaution of upgrading the x264.exe binary to the latest publicly available Rev2085 build for any possible optimizations.



Alas, there is still a great disparity at stock but it does show the same pattern of narrowing when scaling up clock for clock.



CPU - WinRAR 4.10 BETA 1

AMD FX-8150 @ Stock:



Intel i7-2600K @ Stock:



AMD FX-8150 @ 4.7GHz:



Intel i7-2600K @ 4.7GHz:



AMD finally picks up a win here, leading Intel by quite a considerable distance. This could be due to the new instruction sets or something else.

[siopao1984]

Graphics - 3DMark 11 (DX 11 Synthetic)

AMD FX-8150 @ Stock:



Intel i7-2600K @ Stock:



AMD FX-8150 @ 4.7GHz:



Intel i7-2600K @ 4.7GHz:



Overall a narrow win for Intel here but note the huge difference in the Physics subscores between the 2 chips in both the stock and overclocked scenarios. This is more of a GPU intensive benchmark.

[siopao1984]

Graphics - Unigine Heaven DX11 Benchmark 2.5 (DX 11 Synthetic)

Settings:



AMD FX-8150 @ Stock:



Intel i7-2600K @ Stock:



AMD FX-8150 @ 4.7GHz:



Intel i7-2600K @ 4.7GHz:



GPU limited benchmark here - the Intel does have higher Minimum FPS here though

[siopao1984]

Game - Aliens vs Predator DX11

Settings:

Resolution: 1920 x 1200
Texture Quality: 3
Shadow Quality: 3
Anisotropic Filtering: 16
SSAO: ON
Vertical Sync: OFF
DX11 Tessellation: ON
DX11 Advanced Shadows: ON
DX11 MSAA Samples: 4



This is clearly a GPU limited benchmark - the results obtained showed both contenders neck and neck.

Game - Crysis 2 1.9

Settings:





Small win for Intel here - the CryEngine 3 only uses 4 threads properly and is rather GPU limited.



Game - DiRT 3 1.2 (DX11)

Settings:

Resolution: 1920x1200 @ 60Hz

Graphics Quality: Ultra

Anti-Aliasing: 8x MSAA



DiRT 3 is one of the games under the AMD Gaming Evolved "Gamers come first" programme, so it is strange that they're behind Intel in this.