Radeon HD 4870 2GB vs Radeon HD 7950

Intro

Compare those specs to the Radeon HD 7950, which comes with GPU clock speed of 800 MHz, and 1536 MB of GDDR5 RAM set to run at 1250 MHz through a 384-bit bus. It also is made up of 1792 Stream Processors, 112 Texture Address Units, and 32 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4870 2GB		150 Watts
Radeon HD 7950		200 Watts
	Difference: 50 Watts (33%)

Memory Bandwidth

Theoretically speaking, the Radeon HD 7950 should perform quite a bit faster than the Radeon HD 4870 2GB in general. (explain)

Radeon HD 7950		240000 MB/sec
Radeon HD 4870 2GB		115200 MB/sec
	Difference: 124800 (108%)

Texel Rate

The Radeon HD 7950 will be much (more or less 199%) faster with regards to anisotropic filtering than the Radeon HD 4870 2GB. (explain)

Radeon HD 7950		89600 Mtexels/sec
Radeon HD 4870 2GB		30000 Mtexels/sec
	Difference: 59600 (199%)

Pixel Rate

The Radeon HD 7950 is much (approximately 113%) more effective at FSAA than the Radeon HD 4870 2GB, and also capable of handling higher screen resolutions more effectively. (explain)

Radeon HD 7950		25600 Mpixels/sec
Radeon HD 4870 2GB		12000 Mpixels/sec
	Difference: 13600 (113%)

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 information (measured in MB per second) that can be transferred across the external memory interface in one second. It is worked out by multiplying the bus width by its memory clock speed. If the card has DDR type RAM, the result should be multiplied by 2 again. If DDR5, multiply by 4 instead. The better the memory bandwidth, the better the card will be in general. It especially helps with AA, HDR and high resolutions.

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

Pixel Rate: Pixel rate is the most pixels that the graphics chip 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 amount of ROPs by the clock speed of the card. 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 rate is also dependant on lots of other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the ability to reach the max fill rate.