GeForce GTX 660 Ti vs Radeon HD 4890 1GB

Intro

Compare all that to the Radeon HD 4890 1GB, which makes use of a 55 nm design. AMD has set the core frequency at 1000 MHz. The GDDR5 memory works at a frequency of 975 MHz on this card. It features 800(160x5) SPUs along with 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 1GB		190 Watts
	Difference: 40 Watts (27%)

Memory Bandwidth

Theoretically speaking, the GeForce GTX 660 Ti should be 15% quicker than the Radeon HD 4890 1GB in general, due to its greater data rate. (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 is quite a bit (approximately 156%) more effective at AF 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

If running with high levels of AA is important to you, then the GeForce GTX 660 Ti is superior to the Radeon HD 4890 1GB, and very much so. (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 maximum amount of data (measured in MB per second) that can be transported over the external memory interface in a second. It is worked out by multiplying the card's interface width by its memory clock speed. If the card has DDR type RAM, the result should be multiplied by 2 once again. If DDR5, multiply by 4 instead. The higher the bandwidth is, 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 amount of texture map elements (texels) that can be applied in one second. This figure is calculated by multiplying the total texture units of the card by the core clock 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 applied in one second.

Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics card could possibly write to its local memory in a second - measured in millions of pixels per second. The number is worked out by multiplying the amount of ROPs by the the card's clock speed. 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 fill rate also depends 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.