GeForce GTX 660 vs Radeon HD 5870

Intro

Compare those specs to the Radeon HD 5870, which features a core clock frequency of 850 MHz and a GDDR5 memory speed of 1200 MHz. It also uses a 256-bit memory bus, and makes use of a 40 nm design. It is comprised of 1600(320x5) SPUs, 80 Texture Address Units, and 32 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GTX 660		140 Watts
Radeon HD 5870		188 Watts
	Difference: 48 Watts (34%)

Memory Bandwidth

Theoretically speaking, the Radeon HD 5870 is 7% faster than the GeForce GTX 660 overall, because of its higher bandwidth. (explain)

Radeon HD 5870		153600 MB/sec
GeForce GTX 660		144192 MB/sec
	Difference: 9408 (7%)

Texel Rate

The GeForce GTX 660 should be a small bit (more or less 15%) faster with regards to texture filtering than the Radeon HD 5870. (explain)

GeForce GTX 660		78400 Mtexels/sec
Radeon HD 5870		68000 Mtexels/sec
	Difference: 10400 (15%)

Pixel Rate

The Radeon HD 5870 is just a bit (about 16%) faster with regards to full screen anti-aliasing than the GeForce GTX 660, and will be able to handle higher screen resolutions without slowing down too much. (explain)

Radeon HD 5870		27200 Mpixels/sec
GeForce GTX 660		23520 Mpixels/sec
	Difference: 3680 (16%)

Please note that the above 'benchmarks' are all just theoretical - the results were calculated based on the card's specifications, and real-world performance may (and probably will) vary at least a bit.

Price Comparison

Specifications

Memory Bandwidth: Memory bandwidth is the largest amount of data (in units of MB per second) that can be transferred past the external memory interface in a second. The number is calculated by multiplying the interface width by the speed of its memory. If the card has DDR type memory, the result should be multiplied by 2 once again. If DDR5, multiply by 4 instead. The higher the bandwidth is, the better the card will be in general. It especially helps with AA, High Dynamic Range and high resolutions.

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

Pixel Rate: Pixel rate is the most pixels that the graphics chip could possibly write to the local memory in one second - measured in millions of pixels per second. The number is worked out by multiplying the number of ROPs by the the core clock speed. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel output rate also depends on many other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the ability to get to the maximum fill rate.