Radeon HD 4890 1GB vs Radeon HD 7970

Intro

Compare all of that to the Radeon HD 7970, which has a clock speed of 925 MHz and a GDDR5 memory frequency of 1375 MHz. It also uses a 384-bit memory bus, and uses a 28 nm design. It is made up of 2048 SPUs, 128 Texture Address Units, and 32 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4890 1GB		190 Watts
Radeon HD 7970		250 Watts
	Difference: 60 Watts (32%)

Memory Bandwidth

The Radeon HD 7970 should theoretically perform quite a bit faster than the Radeon HD 4890 1GB overall. (explain)

Radeon HD 7970		264000 MB/sec
Radeon HD 4890 1GB		124800 MB/sec
	Difference: 139200 (112%)

Texel Rate

The Radeon HD 7970 will be a lot (approximately 196%) faster with regards to AF than the Radeon HD 4890 1GB. (explain)

Radeon HD 7970		118400 Mtexels/sec
Radeon HD 4890 1GB		40000 Mtexels/sec
	Difference: 78400 (196%)

Pixel Rate

If running with a high resolution is important to you, then the Radeon HD 7970 is the winner, by far. (explain)

Radeon HD 7970		29600 Mpixels/sec
Radeon HD 4890 1GB		16000 Mpixels/sec
	Difference: 13600 (85%)

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 maximum amount of data (measured in megabytes per second) that can be transported across the external memory interface within a second. The number is calculated by multiplying the card's bus width by the speed of its memory. In the case of DDR memory, it should be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The higher the card's memory bandwidth, the better the card will be in general. It especially helps with AA, HDR and higher screen resolutions.

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

Pixel Rate: Pixel rate is the most pixels that the graphics card could possibly write to its local memory in one second - measured in millions of pixels per second. The number is calculated by multiplying the amount of Render Output Units by the the card's clock speed. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel rate is also dependant on many other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the potential to reach the max fill rate.