Radeon HD 4890 1GB vs Radeon HD 6990

Intro

Compare those specs to the Radeon HD 6990, which features a core clock frequency of 830 MHz and a GDDR5 memory frequency of 1250 MHz. It also makes use of a 256-bit bus, and uses a 40 nm design. It is comprised of 1536 SPUs, 96 Texture Address Units, and 32 Raster Operation Units.

Display Graphs

Hide Graphs

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4890 1GB		190 Watts
Radeon HD 6990		375 Watts
	Difference: 185 Watts (97%)

Memory Bandwidth

The Radeon HD 6990, in theory, should perform much faster than the Radeon HD 4890 1GB in general. (explain)

Radeon HD 6990		320000 MB/sec
Radeon HD 4890 1GB		124800 MB/sec
	Difference: 195200 (156%)

Texel Rate

The Radeon HD 6990 should be much (approximately 298%) faster with regards to anisotropic filtering than the Radeon HD 4890 1GB. (explain)

Radeon HD 6990		159360 Mtexels/sec
Radeon HD 4890 1GB		40000 Mtexels/sec
	Difference: 119360 (298%)

Pixel Rate

The Radeon HD 6990 will be a lot (about 232%) better at FSAA than the Radeon HD 4890 1GB, and also capable of handling higher screen resolutions without slowing down too much. (explain)

Radeon HD 6990		53120 Mpixels/sec
Radeon HD 4890 1GB		16000 Mpixels/sec
	Difference: 37120 (232%)

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 max amount of information (counted in MB per second) that can be transported over the external memory interface within a second. The number is calculated by multiplying the interface width by the speed of its memory. In the case of DDR type memory, it must be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The higher the card's memory bandwidth, 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 amount of texture map elements (texels) that are processed in one second. This is worked out by multiplying the total amount of texture units of the card by the core 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 in a second.

Pixel Rate: Pixel rate is the most pixels the graphics card can possibly write to its local memory in a second - measured in millions of pixels per second. The number is calculated by multiplying the amount of Render Output Units by the the core clock speed. ROPs (Raster Operations Pipelines - also sometimes called 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 get to the max fill rate.