GeForce GTX 660 vs Radeon HD 5850

Intro

Compare all of that to the Radeon HD 5850, which features a clock frequency of 725 MHz and a GDDR5 memory frequency of 1000 MHz. It also features a 256-bit memory bus, and uses a 40 nm design. It is made up of 1440(288x5) SPUs, 72 TAUs, and 32 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GTX 660		140 Watts
Radeon HD 5850		151 Watts
	Difference: 11 Watts (8%)

Memory Bandwidth

In theory, the GeForce GTX 660 will be 13% faster than the Radeon HD 5850 overall, because of its higher data rate. (explain)

GeForce GTX 660		144192 MB/sec
Radeon HD 5850		128000 MB/sec
	Difference: 16192 (13%)

Texel Rate

The GeForce GTX 660 is quite a bit (approximately 50%) more effective at anisotropic filtering than the Radeon HD 5850. (explain)

GeForce GTX 660		78400 Mtexels/sec
Radeon HD 5850		52200 Mtexels/sec
	Difference: 26200 (50%)

Pixel Rate

If running with a high resolution is important to you, then the GeForce GTX 660 is a better choice, though not by far. (explain)

GeForce GTX 660		23520 Mpixels/sec
Radeon HD 5850		23200 Mpixels/sec
	Difference: 320 (1%)

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 information (measured in megabytes per second) that can be transferred past the external memory interface in a second. It's calculated by multiplying the card's interface width by the speed of its memory. In the case of DDR type memory, it must be multiplied by 2 again. If DDR5, multiply by 4 instead. The better the memory bandwidth, 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 number of texture map elements (texels) that are applied per second. This is calculated by multiplying the total number of texture units by the core clock 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 a second.

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