NVIDIA GeForce GTX 660 Launch Review

Author: Roger Cantwell
Editor: Howard Ha
Publish Date: Thursday, September 13th, 2012
Originally Published on Neoseeker (http://www.neoseeker.com)
Article Link: http://www.neoseeker.com/Articles/Hardware/Reviews/evga_gtx_660/
Copyright Neo Era Media, Inc. - please do not redistribute or use for commercial purposes.

NVIDIA is showing no mercy in the battle for graphics card supremacy. It has been less than a month since they dropped the GeForce 660 Ti on the masses, yet here we are again as the relentless assault continues with the launch of the GTX 660. You may want to think twice before you begin to compare the GTX 660 against the GTX 660 TI, 670 or even 680 cards, because the GTX 660 is built around the new Kepler GK106 GPU.

The new GK106 retains all of the ground breaking innovations NVIDIA introduced with the release of the GTX 680 including the 28nm fabrication process as well as two major performance increasing features: the Streaming Multiprocessors (SMX) architecture and the incredible GPU Boost technology. The GTX 660 has been trimmed down in a few areas. The number of CUDA cores has been reduced to 960, while the number of Graphics Processing Clusters (GPCs) has dropped to three, one less the GTX 660 Ti.

GPU
GK106
Base Clock
980 MHz
Boost Clock
1033 MHz
Memory Clock (Data rate)
6008 MHz
L2 Cache Size
384KB
Graphics Processing Clusters
3
SMXs
5
CUDA Cores
960
Texture Units
80
ROP Units
24
Total Video Memory
2048MB GDDR5
Memory Interface
192-bit
Total Memory Bandwidth
144.2 GB/s
Texture Filtering Rate (Bilinear)
78.4 GigaTexels/sec
Fabrication Process
28 nm
Transistor Count
2.54 Billion
Connectors
2 x Dual-Link DVI
1 x HDMI
1 x DisplayPort
Form Factor
Dual Slot
Power Connectors
1 x 6-pin
Recommended Power Supply
450 Watts
Thermal Threshold
98° C

 

NVIDIA's new GK106 utilizes a full chip implementation, as well as retaining all of the key features included with the GeForce GTX 680 like NVIDIA's SMX architecture along with the new GPU Boost, which both provide an increase in overall performance. The GK106 is equipped with three Graphics Processing Clusters (GPCs). Each of the GPCs contains its own dedicated raster engine. The GTX 660 also features five next generation Streaming Multiprocessor (SMX) units for a total of 960 CUDA cores that handle the job of pixel, vertex, geometry shading and physx computations alongside the 80 Texture Units. These five SMX units are spread across the three GPCs.

Let's just say that if you were to compare the new GK106 to earlier GeForce GPUs you will find that the new Streaming Multiprocessors offer far more performance when it comes to shaders, textures and geometry processing. At the same time, Kepler's Streaming Multiprocessors use less power while offering twice the performance per watt of the previous generations DirectX 11 GeForce GPUs.

On the memory side of things we again see the use of mixed density memory modules through which NVIDIA is able to equip the GTX 660 with 2GB of memory versus 1.5GB. The GTX 660's memory controllers divide the memory into fragments of 512MB, thereby creating a 1.5GB frame buffer and 192-bit interface. This leaves 512MB accessible through additional memory transactions by the first memory controller at a 64-bit width, while allowing the GPU to utilize the the full 2GB of onboard memory.

NVIDIA's GTX 660 GPU Boost is a mixture of both hardware and software technology. GPU Boost works independently and without the need for game profiles to automatically adjust the GPU's clock speeds, increasing performance as needed. The GTX 660's base clock is set to 980MHz. This is the minimum speed that the base clock will operate while under TDP load, i.e. gaming. This is where the GPU Boost comes in; with a base clock of 980MHz, that leaves room for an additional increase in the base clock to up to 1084MHz or higher, as long as it remains within the predefined power envelope. NVIDIA's GTX 660 has an average power draw of 115W in non TDP programs. When the GTX 660 is overclocked and the power slider is set at 110%, the average power draw will be around 127W in non TDP programs.

NVIDIA's GTX 660 retains all the features and innovations first introduced with the GTX 680. Some of these are supported only on Kepler-based GPUs, while others can be applied to current generation hardware through driver updates.  Let's start with Adaptive VSync.

When enabled, "regular" VSync helps to eliminate screen tearing due to frame rates exceeding a monitor's refresh rate. Unfortunately, with VSync on you will on occasion have screen stuttering; this happens when the frame rate drops below VSync's locked frame rate and again as the frame rate rises back to its normal level.

Adaptive VSync works in combination with VSync by turning the latter off when frame rates drop below VSync's locked rate, and then switching it back on when frame rates return to normal. The stuttering and tearing effect caused by the transition in frame rates are reduced through this combination of features.

Next, FXAA is a new post processing shading technology, which when combined with other post processing such as motion blur and bloom helps reduce aliasing often seen in games. FXAA produces a higher quality image over the standard 4xMSAA setting, while increasing overall performance.

NVIDIA's new TXAA meanwhile has been designed to decrease or eliminate temporal aliasing, which is the crawling or flickering of objects at a location while in motion. TXAA uses a combination of hardware antialiasing and a new custom CG film style anitaliasing resolve with a temporal filter. This gives TXAA the ability to filter any pixel displayed on the screen. By using a mixture of samples from within and outside of the pixel, along with a combination of samples from previous frames, a higher quality of filtering is possible.

Kepler based GPUs support 3D Vision and Surround. With the Kepler based cards, you can now run both technologies on a single card to up to four monitors.

Built around the new GK106 GPU, EVGA's GTX 660 SC Edition packs a lot of power in a small package. Utilizing the same 28nm fabrication process as the GTX 680, the heart of the GK106 GPU has 2.54 billion transistors, 960 CUDA cores, three GPCs, 384KB L2 cache, five SMX units, along with 80 texture units and 24 ROP units.

The GTX 660 SC Edition's base clock is 980MHz with a rated GPU Boost of 1033MHz, however this simply the average boost speed of the card. The 2048MB GDDR5 memory is clocked at 1502MHz (6008MHz effective date rate) on a 192-bit interface, with a total memory bandwidth of 144.2GB/s and a texture filtering rate of 78.4 GigaTexels.

EVGA's GTX 660 SC is completely enclosed in gray plastic. EVGA's logo is found along the leading edge along with GeForce GTX 660 branding.

The PCB itself is shortened to a length of just over 6 inches, for an overall card length of 9.5 inches. The GTX 660 also sees the removal of one 6-pin power supply connection and one of the SLI connections.

The EVGA GTX 660 SC Edition's backplate is equipped with two dual link DVI connectors, one HDMI port that supports 1080P along with 1.4a features, and a full size DisplayPort. The redesigned backplate also offers support for the new 3D Vision and Surround technologies up to 2560x1600 pixels in resolution through both the Dual link DVI and DisplayPort outputs.

EVGA uses the slightly larger heatsink found on the reference card with the GTX 660 SC Edition as well, which of course serves to greatly increase cooling performance. The heatsink itself still utilizes the stacked fin design with the heatpipes attached to the cooler. One notable difference is the removal of the aluminum heatsink from the front of the PCB that was used on the GTX 660 Ti. This may be due to the fact that the GTX 660 SC has a maximum TDP of 140W.

NVIDIA utilizes a one piece design for the fan and cooler assembly, unlike the one used for the GTX 660 Ti. Looking at the placement of the thermal pads we can see that NVIDIA shifted more of the power circuitry toward the rear of the PCB, placing it closer to the fan.

The GTX 660's memory placement is also different from that of the GTX 660 Ti, as the memory has been moved forward on the PCB. With this move, NVIDIA has placed thermal pads on the memory for added cooling efficiency.

On the backside of the PCB we can see the four additional chips of GDDR5 memory.

Overclocking

From with a base clock of 980MHz, we wanted to see how well the GPU Boost technology works with no adjustments to the power target slider or offsets and using NVIDIA's OC Scanner to test the GTX 660 SC edition. The end result of the GPU Boost was 1045MHz, a 6.6% increase in performance over the base clock of 980MHz.

Next we wanted to see what kind of overclock we could manage using the power target slider. We set the power target for 110%, the GPU offset to 70% and the memory offset to 55% which gave us a final overclock of 1215MHz.

Hardware Configuration

Test Setup:

Drivers:

Benchmarks DX 11:

Test Settings

All benchmarks will be performed at a resolution of 1920x1080 when using a single display. A resolution of 5760x1080 will be used for Benchmarks in Eyefinity & Surround. Vsync will be disabled in the control panel, AA will be set to x4 with AF set to x16, all in-game settings will be set to high, or very high.

Usage:

Comparison Cards:

Batman: Arkham City was built using the Unreal 3 Engine, and contains areas that makes use of extreme tessellation along with high resolution textures and dynamic lighting. Combining all of these features together makes for a graphically stunning game.

The GTX 660 didn't exactly power through 5760x1080, but still presented a playable frame rate.

Battlefield 3 is an intense FPS with massive battles that utilize the Frostbite 2 engine for features like Dynamic Global illumination along with deferred shading, adding unmatched realism to the game and enabling it to accurately render destroyed buildings, burnt-out cars and highly populated areas.

BF3 is easily playable at 1920x1080, scoring 57FPS.

It's a different story at 5760x1080, though by turning down the eye-candy you might get a few extra frames per second.

Crysis 2 is a first-person shooter developed by Crytek and is built on the CryEngine 3 engine. While the game was lacking in graphical fidelity upon its release, Crytek has since added features such as DX11 and high quality textures. This improved the in-game visuals substantially, which in turn pushes even high-end hardware to the max.

The GTX 660 shows the upgrade potential it offers by delivering 60FPS in Crysis 2 at 1920x1080 with high settings.

Crysis 2 remains a beast especially at 5760x1080.

DiRT 3 takes full advantage of D11's latest features, making it one of the most visually impressive additions to the series yet thanks to tessellation and SM5.

The GTX 660 seemed to have a little harder time with DiRT 3.

Futuremark's latest 3DMark 2011 is designed for testing DirectX 11 hardware running on Windows 7 and Windows Vista. The benchmark includes six all new benchmark tests that make extensive use of all the new DirectX 11 features including tessellation, compute shaders and multi-threading.

Total War: Shogun 2 is great game that blends two gameplay styles, turn based and real time strategy, to create a unique experience. The game is set in 16th-century feudal Japan, placing you in control of a warlord battling various rival factions. Total War: Shogun 2 is the first in the series to feature DX11 technologies to enhance the look of the game, which along with the massive battles can bring even the highest-end graphics cards to their knees.

The GTX 660 SC Edition performed almost as well as the HD 7970 at 1920x1080.

Again the GTX 660 SC is closing in on the HD 7970 at 5760x1080.

Unigine Heaven 3.0 is one of the most popular DirectX 11 benchmarks used today. With its ability for extreme tessellation, it creates a truly stunning spectacle.

The GTX 660 made an impressive showing at 1920x1080, with extreme tessellation toggled on.

To measure the GPU temperatures, we ran two game benchmarks and recorded the idle and load temperature according to the minimum and maximum temperatures posted by MSI Afterburner. The software we tested were Crysis 2 and Unigine Heaven 3.0, running both benchmarks for 15 minutes each. This way we can give the included thermal solution and GPU time to reach equilibrium.

To measure power usage, a Kill A Watt power meter was used. Note that the numbers represent the power drain for the entire benchmarking system, not just the video cards themselves. For the idle readings we measured the power drain from the desktop, with no applications running. For load testing, we took the sustained peak power drain readings after running the system through the same in-game benchmarks we used for the temperature testing. This way we are recording real world power usage as opposed to pushing a product to its thermal threshold.

NVIDIA's GeForce GTX 660 is a great option for those looking to upgrade from the previous generation GPUs at the more attractive price segment of $229, without sacrificing performance. The GTX 660 is based on the new Kepler GK106 GPU and retains all the features found in the GTX 680, as well as utilizing the 28nm fabrication process.

NVIDIA packed in 2.54 billion transistors along with 960 CUDA cores, 5 SMX units, 3 GPCs, 80 texture units, and 24 ROP units. The GTX 660's base clock is 980MHz with an average boost clock of 1033MHz, while the 2GB GDDR5 is clocked at (6008MHz effective). The 2GB memory runs on a 192-bit interface with 144.2GB/s memory bandwidth.

NVIDIA's GTX 660 offers best-in-class performance while gaming at 1920x1080. Included are features that will greatly enhance game play like Physx, Adaptive VSync and TXAA- you won't find those on Team Red's GPUs. Performance wise, the GTX 660 can be up to 60% faster that the GTX 460 and it is five times faster in BF3 when compared to some of the prior generation graphics solutions.

Once again NVIDIA hits the sweet spot for performance versus price. The GTX 660 is a tremendous value for those looking to upgrade from older generation GPUs.

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