Radeon HD 4870 512MB vs Radeon HD 6990

Intro

Compare those specs to the Radeon HD 6990, which comes with core speeds of 830 MHz on the GPU, and 1250 MHz on the 2048 MB of GDDR5 RAM. It features 1536 SPUs as well as 96 TAUs and 32 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4870 512MB		150 Watts
Radeon HD 6990		375 Watts
	Difference: 225 Watts (150%)

Memory Bandwidth

In theory, the Radeon HD 6990 should perform quite a bit faster than the Radeon HD 4870 512MB in general. (explain)

Radeon HD 6990		320000 MB/sec
Radeon HD 4870 512MB		115200 MB/sec
	Difference: 204800 (178%)

Texel Rate

The Radeon HD 6990 is a lot (about 431%) faster with regards to anisotropic filtering than the Radeon HD 4870 512MB. (explain)

Radeon HD 6990		159360 Mtexels/sec
Radeon HD 4870 512MB		30000 Mtexels/sec
	Difference: 129360 (431%)

Pixel Rate

The Radeon HD 6990 is quite a bit (approximately 343%) faster with regards to AA than the Radeon HD 4870 512MB, and also able to handle higher resolutions more effectively. (explain)

Radeon HD 6990		53120 Mpixels/sec
Radeon HD 4870 512MB		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: Memory bandwidth is the largest amount of data (measured in megabytes per second) that can be transported over the external memory interface in one second. The number is calculated by multiplying the bus width by the speed of its memory. If the card has DDR type memory, the result should be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The better the card's memory bandwidth, the faster the card will be in general. It especially helps with AA, HDR and higher screen resolutions.

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

Pixel Rate: Pixel rate is the most pixels that the graphics chip can possibly write to the local memory in one second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the number of ROPs by the clock speed of the card. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel output rate also depends on lots of other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the potential to reach the max fill rate.