Radeon HD 4790 vs Radeon HD 7790

Intro

Compare that to the Radeon HD 7790, which has core clock speeds of 1000 MHz on the GPU, and 1500 MHz on the 1024 MB of GDDR5 RAM. It features 896 SPUs as well as 56 Texture Address Units and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Memory Bandwidth

The Radeon HD 4790, in theory, should perform a small bit faster than the Radeon HD 7790 in general. (explain)

Radeon HD 4790		102400 MB/sec
Radeon HD 7790		96000 MB/sec
	Difference: 6400 (7%)

Texel Rate

The Radeon HD 7790 will be quite a bit (approximately 192%) more effective at AF than the Radeon HD 4790. (explain)

Radeon HD 7790		56000 Mtexels/sec
Radeon HD 4790		19200 Mtexels/sec
	Difference: 36800 (192%)

Pixel Rate

The Radeon HD 7790 is much (more or less 67%) better at full screen anti-aliasing than the Radeon HD 4790, and also able to handle higher resolutions while still performing well. (explain)

Radeon HD 7790		16000 Mpixels/sec
Radeon HD 4790		9600 Mpixels/sec
	Difference: 6400 (67%)

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: Bandwidth is the largest amount of information (measured in megabytes per second) that can be transported across the external memory interface in a second. It's calculated by multiplying the bus width by its memory clock speed. If the card has DDR memory, it should be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The higher the bandwidth is, the faster the card will be in general. It especially helps with anti-aliasing, HDR and higher screen resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that are applied in one second. This figure is worked out by multiplying the total number of texture units of the card by the core clock speed of the chip. The better this number, the better the 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 maximum amount of pixels that the graphics card can possibly record to the local memory per second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the number of colour ROPs by the clock speed of the card. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel fill rate also depends on many other factors, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to reach the maximum fill rate.