GeForce GTX 660 vs Radeon HD 4890 1GB

Intro

Compare those specifications to the Radeon HD 4890 1GB, which makes use of a 55 nm design. AMD has clocked the core speed at 1000 MHz. The GDDR5 RAM works at a speed of 975 MHz on this specific model. 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		140 Watts
Radeon HD 4890 1GB		190 Watts
	Difference: 50 Watts (36%)

Memory Bandwidth

The GeForce GTX 660 should theoretically be just a bit faster than the Radeon HD 4890 1GB in general. (explain)

GeForce GTX 660		144192 MB/sec
Radeon HD 4890 1GB		124800 MB/sec
	Difference: 19392 (16%)

Texel Rate

The GeForce GTX 660 should be much (more or less 96%) more effective at AF than the Radeon HD 4890 1GB. (explain)

GeForce GTX 660		78400 Mtexels/sec
Radeon HD 4890 1GB		40000 Mtexels/sec
	Difference: 38400 (96%)

Pixel Rate

If running with high levels of AA is important to you, then the GeForce GTX 660 is the winner, by far. (explain)

GeForce GTX 660		23520 Mpixels/sec
Radeon HD 4890 1GB		16000 Mpixels/sec
	Difference: 7520 (47%)

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 data (measured in megabytes per second) that can be moved past the external memory interface in one second. It is worked out by multiplying the interface width by its memory speed. In the case of DDR RAM, it should be multiplied by 2 once again. If DDR5, multiply by 4 instead. The better the card's memory bandwidth, the faster the card will be in general. It especially helps with AA, HDR and higher screen resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that can be processed in one second. This number is calculated by multiplying the total number of texture units by the core speed of the chip. The higher this number, the better the graphics 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 most pixels that the graphics card can possibly record to the local memory in one second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the number of ROPs by the the core clock speed. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel rate also depends on quite a few other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to get to the maximum fill rate.