Radeon HD 4790 vs Radeon HD 7790

Intro

Compare all 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 TAUs and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Memory Bandwidth

Performance-wise, the Radeon HD 4790 should in theory be a bit better 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 a lot (approximately 192%) faster with regards to AF than the Radeon HD 4790. (explain)

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

Pixel Rate

If using a high resolution is important to you, then the Radeon HD 7790 is the winner, by far. (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 max amount of information (in units of MB per second) that can be moved across the external memory interface in a second. The number is calculated by multiplying the card's bus width by its memory speed. In the case of DDR RAM, the result 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 AA, High Dynamic Range and high resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that can be applied in one second. This is calculated by multiplying the total number of texture units of the card by the core speed of the chip. The better this number, the better the graphics card will be at handling 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 the graphics card can possibly write to its local memory in a second - measured in millions of pixels per second. The figure is worked out by multiplying the number of colour ROPs by the the card's clock speed. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel output rate also depends on lots of other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the potential to reach the maximum fill rate.