Radeon HD 4890 1GB vs Radeon HD 7950

Intro

Compare those specifications to the Radeon HD 7950, which comes with clock speeds of 800 MHz on the GPU, and 1250 MHz on the 1536 MB of GDDR5 memory. It features 1792 SPUs along with 112 Texture Address Units and 32 Rasterization Operator Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4890 1GB		190 Watts
Radeon HD 7950		200 Watts
	Difference: 10 Watts (5%)

Memory Bandwidth

Theoretically speaking, the Radeon HD 7950 should be 92% quicker than the Radeon HD 4890 1GB in general, because of its greater bandwidth. (explain)

Radeon HD 7950		240000 MB/sec
Radeon HD 4890 1GB		124800 MB/sec
	Difference: 115200 (92%)

Texel Rate

The Radeon HD 7950 should be a lot (about 124%) faster with regards to AF than the Radeon HD 4890 1GB. (explain)

Radeon HD 7950		89600 Mtexels/sec
Radeon HD 4890 1GB		40000 Mtexels/sec
	Difference: 49600 (124%)

Pixel Rate

The Radeon HD 7950 should be a lot (more or less 60%) faster with regards to AA than the Radeon HD 4890 1GB, and will be able to handle higher screen resolutions better. (explain)

Radeon HD 7950		25600 Mpixels/sec
Radeon HD 4890 1GB		16000 Mpixels/sec
	Difference: 9600 (60%)

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 largest amount of data (counted in MB per second) that can be transferred over the external memory interface in a second. The number is calculated by multiplying the bus width by its memory speed. If it uses DDR type memory, the result should be multiplied by 2 once again. If DDR5, multiply by 4 instead. The better the bandwidth is, the faster the card will be in general. It especially helps with anti-aliasing, HDR and high resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that can be processed per second. This is calculated by multiplying the total amount of texture units by the core clock speed of the chip. The higher the texel rate, the better the video card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed per second.

Pixel Rate: Pixel rate is the maximum number of pixels that the graphics card can possibly record to the local memory per second - measured in millions of pixels per second. The number is calculated by multiplying the number of Raster Operations Pipelines by the clock speed of the card. ROPs (Raster Operations Pipelines - aka 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 of the card - the lower the bandwidth is, the lower the ability to reach the maximum fill rate.