GeForce GTX 660 Ti vs Radeon HD 4890 2GB

Intro

Compare that to the Radeon HD 4890 2GB, which has a GPU core clock speed of 1000 MHz, and 2048 MB of GDDR5 memory running at 975 MHz through a 256-bit bus. It also features 800(160x5) Stream Processors, 40 TAUs, and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GTX 660 Ti		150 Watts
Radeon HD 4890 2GB		190 Watts
	Difference: 40 Watts (27%)

Memory Bandwidth

As far as performance goes, the GeForce GTX 660 Ti should in theory be a little bit better than the Radeon HD 4890 2GB in general. (explain)

GeForce GTX 660 Ti		144000 MB/sec
Radeon HD 4890 2GB		124800 MB/sec
	Difference: 19200 (15%)

Texel Rate

The GeForce GTX 660 Ti will be quite a bit (more or less 156%) more effective at texture filtering than the Radeon HD 4890 2GB. (explain)

GeForce GTX 660 Ti		102480 Mtexels/sec
Radeon HD 4890 2GB		40000 Mtexels/sec
	Difference: 62480 (156%)

Pixel Rate

If running with lots of anti-aliasing is important to you, then the GeForce GTX 660 Ti is superior to the Radeon HD 4890 2GB, by far. (explain)

GeForce GTX 660 Ti		21960 Mpixels/sec
Radeon HD 4890 2GB		16000 Mpixels/sec
	Difference: 5960 (37%)

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: Bandwidth is the largest amount of information (in units of MB per second) that can be transferred across the external memory interface in one second. The number is worked out by multiplying the interface width by its memory clock speed. If it uses DDR type RAM, it must be multiplied by 2 once again. If DDR5, multiply by ANOTHER 2x. The higher the bandwidth is, the faster the card will be in general. It especially helps with anti-aliasing, HDR and higher screen resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that are applied per second. This number is calculated by multiplying the total texture units of the card by the core 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 a second.

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