GeForce GTX 660 vs Radeon HD 4870 512MB

Intro

Compare all that to the Radeon HD 4870 512MB, which features clock speeds of 750 MHz on the GPU, and 900 MHz on the 512 MB of GDDR5 RAM. It features 800(160x5) SPUs as well as 40 TAUs and 16 Rasterization Operator Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GTX 660		140 Watts
Radeon HD 4870 512MB		150 Watts
	Difference: 10 Watts (7%)

Memory Bandwidth

As far as performance goes, the GeForce GTX 660 should theoretically be a lot superior to the Radeon HD 4870 512MB in general. (explain)

GeForce GTX 660		144192 MB/sec
Radeon HD 4870 512MB		115200 MB/sec
	Difference: 28992 (25%)

Texel Rate

The GeForce GTX 660 should be quite a bit (about 161%) more effective at anisotropic filtering than the Radeon HD 4870 512MB. (explain)

GeForce GTX 660		78400 Mtexels/sec
Radeon HD 4870 512MB		30000 Mtexels/sec
	Difference: 48400 (161%)

Pixel Rate

The GeForce GTX 660 should be a lot (approximately 96%) better at anti-aliasing than the Radeon HD 4870 512MB, and capable of handling higher resolutions better. (explain)

GeForce GTX 660		23520 Mpixels/sec
Radeon HD 4870 512MB		12000 Mpixels/sec
	Difference: 11520 (96%)

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 maximum amount of data (measured in megabytes per second) that can be moved across the external memory interface within a second. It's calculated by multiplying the card's bus width by its memory speed. If the card has DDR type RAM, it should be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. 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 number of texture map elements (texels) that can be processed per second. This figure is calculated by multiplying the total amount of texture units of the card by the core clock speed of the chip. The better the texel rate, the better the card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in a second.

Pixel Rate: Pixel rate is the maximum number of pixels the video card could possibly record to its local memory in one second - measured in millions of pixels per second. The number is calculated by multiplying the amount of Raster Operations Pipelines by the clock speed of the card. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel rate is also dependant on lots of other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the ability to get to the maximum fill rate.