GeForce GTX 660 Ti vs Radeon HD 4890 1GB

Intro

Compare that to the Radeon HD 4890 1GB, which has core speeds of 1000 MHz on the GPU, and 975 MHz on the 1024 MB of GDDR5 RAM. It features 800(160x5) SPUs as well as 40 Texture Address Units and 16 Rasterization Operator Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GTX 660 Ti		150 Watts
Radeon HD 4890 1GB		190 Watts
	Difference: 40 Watts (27%)

Memory Bandwidth

The GeForce GTX 660 Ti, in theory, should be a bit faster than the Radeon HD 4890 1GB overall. (explain)

GeForce GTX 660 Ti		144000 MB/sec
Radeon HD 4890 1GB		124800 MB/sec
	Difference: 19200 (15%)

Texel Rate

The GeForce GTX 660 Ti should be much (approximately 156%) faster with regards to texture filtering than the Radeon HD 4890 1GB. (explain)

GeForce GTX 660 Ti		102480 Mtexels/sec
Radeon HD 4890 1GB		40000 Mtexels/sec
	Difference: 62480 (156%)

Pixel Rate

The GeForce GTX 660 Ti will be quite a bit (approximately 37%) better at FSAA than the Radeon HD 4890 1GB, and capable of handling higher screen resolutions without losing too much performance. (explain)

GeForce GTX 660 Ti		21960 Mpixels/sec
Radeon HD 4890 1GB		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: Memory bandwidth is the max amount of information (measured in megabytes per second) that can be transferred past the external memory interface within a second. It is worked out by multiplying the card's interface width by its memory speed. If the card has DDR type RAM, it must be multiplied by 2 once again. If DDR5, multiply by ANOTHER 2x. The higher the card's memory bandwidth, the better the card will be in general. It especially helps with anti-aliasing, HDR and higher screen resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that are applied per second. This 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 texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in a second.

Pixel Rate: Pixel rate is the most pixels the graphics card could possibly record to its local memory per second - measured in millions of pixels per second. The number is calculated 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 filling the screen with pixels (the image). The actual pixel fill rate is also dependant on many other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the ability to reach the maximum fill rate.