GeForce GTX 660 vs Radeon HD 6790

Intro

The GeForce GTX 660 makes use of a 28 nm design. nVidia has clocked the core frequency at 980 MHz. The GDDR5 memory works at a frequency of 1502 MHz on this card. It features 960 SPUs as well as 80 TAUs and 24 Rasterization Operator Units.

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

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

Radeon HD 6790 Amazon.com Other US-based stores

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: Bandwidth is the maximum amount of data (counted in MB per second) that can be transferred past the external memory interface in a second. The number is worked out by multiplying the interface width by its memory speed. In the case of DDR type RAM, the result should be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The higher the bandwidth is, the faster the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and high resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that can be applied per second. This number is worked out by multiplying the total texture units of the card by the core clock speed of the chip. The better this number, the better the card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels per second.

Pixel Rate: Pixel rate is the maximum number of pixels the graphics card can possibly write to its local memory in one second - measured in millions of pixels per second. The number is worked out by multiplying the number of colour ROPs by the the card's clock speed. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel output rate also depends on quite a few other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the ability to get to the max fill rate.