GeForce GTX 660 vs Radeon HD 6790

Intro

The GeForce GTX 660 comes with a GPU core speed of 980 MHz, and the 2048 MB of GDDR5 RAM runs at 1502 MHz through a 192-bit bus. It also features 960 SPUs, 80 TAUs, and 24 Raster Operation Units.

Compare all that to the Radeon HD 6790, which features clock speeds of 840 MHz on the GPU, and 1050 MHz on the 1024 MB of GDDR5 memory. It features 800 SPUs along with 40 Texture Address Units and 16 Rasterization Operator Units.

Price Comparison

Please note that the price comparisons are based on search keywords, and might not be the exact same card listed on this page. We have no control over the accuracy of their search results.

GeForce GTX 660 Amazon.com Other US-based stores Amazon.co.uk Amazon.de Amazon.fr

Radeon HD 6790 Amazon.com Other US-based stores Amazon.co.uk Amazon.de Amazon.fr

Specifications

Model	GeForce GTX 660	Radeon HD 6790
Manufacturer	nVidia	ATi
Year	September 2012	April 2011
Code Name	GK106	Barts LE
Fab Process	28 nm	40 nm
Bus	PCIe 3.0 x16	PCIe 2.1 x16
Memory	2048 MB	1024 MB
Core Speed	980 MHz	840 MHz
Shader Speed	980 MHz	(N/A) MHz
Memory Speed	1502 MHz (6008 MHz effective)	1050 MHz (4200 MHz effective)
Unified Shaders	960	800
Texture Mapping Units	80	40
Render Output Units	24	16
Bus Type	GDDR5	GDDR5
Bus Width	192-bit	256-bit
DirectX Version	DirectX 11.1	DirectX 11
OpenGL Version	OpenGL 4.3	OpenGL 4.1
Power (Max TDP)	140 watts	150 watts
Shader Model	5.0	5.0
Bandwidth	144192 MB/sec	134400 MB/sec
Texel Rate	78400 Mtexels/sec	33600 Mtexels/sec
Pixel Rate	23520 Mpixels/sec	13440 Mpixels/sec

Memory Bandwidth: Memory bandwidth is the maximum amount of data (measured in megabytes per second) that can be transferred over the external memory interface in a second. The number is calculated by multiplying the card's bus width by its memory clock speed. In the case of DDR type RAM, the result should be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The higher the bandwidth is, the better the card will be in general. It especially helps with anti-aliasing, HDR and high resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that are processed in one second. This figure is calculated by multiplying the total texture units of the card by the core speed of the chip. The better the texel rate, the better the video card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels in one second.

Pixel Rate: Pixel rate is the maximum amount of pixels the graphics card could possibly record to its local memory in a second - measured in millions of pixels per second. The figure is calculated by multiplying the amount of ROPs by the the card's clock speed. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel fill rate also depends on quite a few other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the ability to reach the maximum fill rate.