Radeon HD 4770 vs Radeon HD 7790

Intro

Compare all that to the Radeon HD 7790, which features 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

Power Consumption (Max TDP)

Radeon HD 4770		80 Watts
Radeon HD 7790		85 Watts
	Difference: 5 Watts (6%)

Memory Bandwidth

Performance-wise, the Radeon HD 7790 should theoretically be much superior to the Radeon HD 4770 in general. (explain)

Radeon HD 7790		96000 MB/sec
Radeon HD 4770		51200 MB/sec
	Difference: 44800 (88%)

Texel Rate

The Radeon HD 7790 will be a lot (about 133%) better at AF than the Radeon HD 4770. (explain)

Radeon HD 7790		56000 Mtexels/sec
Radeon HD 4770		24000 Mtexels/sec
	Difference: 32000 (133%)

Pixel Rate

If running with a high screen resolution is important to you, then the Radeon HD 7790 is the winner, by a large margin. (explain)

Radeon HD 7790		16000 Mpixels/sec
Radeon HD 4770		12000 Mpixels/sec
	Difference: 4000 (33%)

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 max amount of information (counted in MB per second) that can be moved over the external memory interface within a second. It's calculated by multiplying the interface width by its memory speed. If it uses DDR RAM, it should be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The better the bandwidth is, the better the card will be in general. It especially helps with anti-aliasing, HDR and higher screen resolutions.

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

Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics chip can possibly record to its local memory per second - measured in millions of pixels per second. The number is worked out by multiplying the number of Render Output Units by the clock speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel rate also depends on quite a few other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to reach the max fill rate.