Radeon HD 4870 2GB vs Radeon HD 6990

Intro

Compare those specs to the Radeon HD 6990, which has core speeds of 830 MHz on the GPU, and 1250 MHz on the 2048 MB of GDDR5 memory. It features 1536 SPUs as well as 96 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 6990		375 Watts
	Difference: 225 Watts (150%)

Memory Bandwidth

Performance-wise, the Radeon HD 6990 should theoretically be a lot better than the Radeon HD 4870 2GB in general. (explain)

Radeon HD 6990		320000 MB/sec
Radeon HD 4870 2GB		115200 MB/sec
	Difference: 204800 (178%)

Texel Rate

The Radeon HD 6990 should be a lot (more or less 431%) faster with regards to texture filtering than the Radeon HD 4870 2GB. (explain)

Radeon HD 6990		159360 Mtexels/sec
Radeon HD 4870 2GB		30000 Mtexels/sec
	Difference: 129360 (431%)

Pixel Rate

The Radeon HD 6990 is much (approximately 343%) faster with regards to anti-aliasing than the Radeon HD 4870 2GB, and will be able to handle higher screen resolutions better. (explain)

Radeon HD 6990		53120 Mpixels/sec
Radeon HD 4870 2GB		12000 Mpixels/sec
	Difference: 41120 (343%)

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.

One or more cards in this comparison are multi-core. This means that their bandwidth, texel and pixel rates are theoretically doubled - this does not mean the card will actually perform twice as fast, but only that it should in theory be able to. Actual game benchmarks will give a more accurate idea of what it's capable of.

Price Comparison

Specifications

Memory Bandwidth: Bandwidth is the maximum amount of data (counted in MB per second) that can be transferred past the external memory interface within a second. It is worked out by multiplying the card's interface width by its memory clock speed. If the card has DDR memory, the result should be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The higher the bandwidth is, the better the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and higher screen resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that are processed in one second. This number is calculated by multiplying the total 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 processed in one second.

Pixel Rate: Pixel rate is the maximum amount of pixels the graphics card could possibly record 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 many other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the potential to reach the maximum fill rate.