Radeon HD 4890 2GB vs Radeon HD 7950

Intro

Compare all of that to the Radeon HD 7950, which uses a 28 nm design. AMD has clocked the core frequency at 800 MHz. The GDDR5 memory runs at a frequency of 1250 MHz on this specific model. It features 1792 SPUs as well as 112 TAUs and 32 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4890 2GB		190 Watts
Radeon HD 7950		200 Watts
	Difference: 10 Watts (5%)

Memory Bandwidth

The Radeon HD 7950 should in theory perform a lot faster than the Radeon HD 4890 2GB overall. (explain)

Radeon HD 7950		240000 MB/sec
Radeon HD 4890 2GB		124800 MB/sec
	Difference: 115200 (92%)

Texel Rate

The Radeon HD 7950 will be a lot (more or less 124%) faster with regards to anisotropic filtering than the Radeon HD 4890 2GB. (explain)

Radeon HD 7950		89600 Mtexels/sec
Radeon HD 4890 2GB		40000 Mtexels/sec
	Difference: 49600 (124%)

Pixel Rate

The Radeon HD 7950 should be a lot (about 60%) better at full screen anti-aliasing than the Radeon HD 4890 2GB, and will be able to handle higher screen resolutions more effectively. (explain)

Radeon HD 7950		25600 Mpixels/sec
Radeon HD 4890 2GB		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 max amount of data (in units of MB per second) that can be transported past the external memory interface in one second. It is calculated by multiplying the card's bus width by its memory clock speed. If it uses DDR RAM, the result should be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The better the card's memory bandwidth, the better the card will be in general. It especially helps with anti-aliasing, HDR and higher screen resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that are processed in one second. This number is calculated by multiplying the total amount of texture units by the core speed of the chip. The better this number, the better the card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed in one second.

Pixel Rate: Pixel rate is the maximum amount of pixels the graphics card can possibly record to its local memory per second - measured in millions of pixels per second. The number is calculated by multiplying the number of ROPs by the the core 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 rate is also dependant on quite a few other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to get to the max fill rate.