Radeon HD 4770 vs Radeon HD 7790

Intro

Compare all of that to the Radeon HD 7790, which comes with GPU core speed of 1000 MHz, and 1024 MB of GDDR5 memory set to run at 1500 MHz through a 128-bit bus. It also features 896 Stream Processors, 56 Texture Address Units, 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 better than 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 should be much (more or less 133%) more effective at anisotropic filtering 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 resolution is important to you, then the Radeon HD 7790 is the winner, by far. (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 largest amount of data (in units of megabytes per second) that can be transferred past the external memory interface in a second. The number is worked out by multiplying the card's interface width by its memory speed. In the case of DDR type memory, it should be multiplied by 2 once again. If DDR5, multiply by 4 instead. The higher the card's memory bandwidth, 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 amount of texture map elements (texels) that can be processed in one second. This figure 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 texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in a second.

Pixel Rate: Pixel rate is the most pixels the graphics card could 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 Raster Operations Pipelines by the the core speed of the card. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel rate also depends on quite a few other factors, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to get to the maximum fill rate.