Radeon HD 4890 2GB vs Radeon HD 7790

Intro

Compare those specifications to the Radeon HD 7790, which has a clock frequency of 1000 MHz and a GDDR5 memory speed of 1500 MHz. It also makes use of a 128-bit memory bus, and makes use of a 28 nm design. It is comprised of 896 SPUs, 56 Texture Address Units, and 16 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 7790		85 Watts
Radeon HD 4890 2GB		190 Watts
	Difference: 105 Watts (124%)

Memory Bandwidth

As far as performance goes, the Radeon HD 4890 2GB should theoretically be quite a bit superior to the Radeon HD 7790 in general. (explain)

Radeon HD 4890 2GB		124800 MB/sec
Radeon HD 7790		96000 MB/sec
	Difference: 28800 (30%)

Texel Rate

The Radeon HD 7790 is a lot (more or less 40%) more effective at AF than the Radeon HD 4890 2GB. (explain)

Radeon HD 7790		56000 Mtexels/sec
Radeon HD 4890 2GB		40000 Mtexels/sec
	Difference: 16000 (40%)

Pixel Rate

Both cards have the exact same pixel rate, so theoretically they should be equally good at at anti-aliasing, and be able to handle the same screen resolutions. (explain)

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 information (measured in megabytes per second) that can be transferred across the external memory interface in a second. It's calculated by multiplying the interface width by the speed of its memory. In the case of DDR memory, it should be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The higher the bandwidth is, the faster the card will be in general. It especially helps with anti-aliasing, HDR and high resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that are applied per second. This is calculated by multiplying the total texture units of the card by the core clock speed of the chip. The higher this number, 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 could possibly record to its local memory per second - measured in millions of pixels per second. The figure is calculated by multiplying the amount of colour 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 rate is also dependant on quite a few other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the ability to get to the maximum fill rate.