GeForce GT 420 vs Radeon HD 4890 1GB

Intro

Compare that to the Radeon HD 4890 1GB, which features core speeds of 1000 MHz on the GPU, and 975 MHz on the 1024 MB of GDDR5 memory. 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 GT 420		50 Watts
Radeon HD 4890 1GB		190 Watts
	Difference: 140 Watts (280%)

Memory Bandwidth

Theoretically, the Radeon HD 4890 1GB should be quite a bit faster than the GeForce GT 420 in general. (explain)

Radeon HD 4890 1GB		124800 MB/sec
GeForce GT 420		28800 MB/sec
	Difference: 96000 (333%)

Texel Rate

The Radeon HD 4890 1GB will be much (more or less 614%) faster with regards to anisotropic filtering than the GeForce GT 420. (explain)

Radeon HD 4890 1GB		40000 Mtexels/sec
GeForce GT 420		5600 Mtexels/sec
	Difference: 34400 (614%)

Pixel Rate

If using lots of anti-aliasing is important to you, then the Radeon HD 4890 1GB is a better choice, by far. (explain)

Radeon HD 4890 1GB		16000 Mpixels/sec
GeForce GT 420		2800 Mpixels/sec
	Difference: 13200 (471%)

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 megabytes per second) that can be transferred across the external memory interface in one second. It is calculated by multiplying the interface width by the speed of its memory. If the card has DDR RAM, it must be multiplied by 2 once again. If DDR5, multiply by ANOTHER 2x. The better the bandwidth is, the faster the card will be in general. It especially helps with AA, High Dynamic Range and higher screen resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that can be applied in one second. This figure is calculated by multiplying the total amount of texture units by the core clock speed of the chip. The better 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 most pixels that the graphics chip can possibly write to the local memory per second - measured in millions of pixels per second. The number is calculated by multiplying the amount of Raster Operations Pipelines by the clock speed of the card. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel rate also depends on lots of other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the ability to reach the max fill rate.