GeForce GTX 660 Ti vs Radeon HD 4890 2GB

Intro

Compare that to the Radeon HD 4890 2GB, which uses a 55 nm design. AMD has set the core speed at 1000 MHz. The GDDR5 memory works at a speed of 975 MHz on this particular card. It features 800(160x5) SPUs as well as 40 TAUs and 16 Rasterization Operator Units.

Display Graphs

Hide Graphs

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

The GeForce GTX 660 Ti, in theory, should be a bit faster than the Radeon HD 4890 2GB overall. (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 should be much (more or less 156%) better at AF 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 using high levels of AA is important to you, then the GeForce GTX 660 Ti is a better choice, 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: Memory bandwidth is the max amount of data (counted in megabytes per second) that can be transported across the external memory interface in a second. The number is worked out by multiplying the interface width by its memory clock speed. If the card has DDR type RAM, the result should be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The better the memory bandwidth, the better the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and higher screen resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that are applied in one second. This figure is worked out by multiplying the total texture units by the core 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 in a second.

Pixel Rate: Pixel rate is the most pixels that the graphics card can possibly write to the local memory in a second - measured in millions of pixels per second. The figure is calculated by multiplying the amount of colour ROPs by the the card's clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel output rate also depends on many other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the potential to reach the max fill rate.