Radeon HD 4770 vs Radeon HD 7950 3GB

Intro

Compare all of that to the Radeon HD 7950 3GB, which has a clock speed of 800 MHz and a GDDR5 memory speed of 1250 MHz. It also makes use of a 384-bit memory bus, and makes use of a 28 nm design. It features 1792 SPUs, 112 Texture Address Units, and 32 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4770		80 Watts
Radeon HD 7950 3GB		200 Watts
	Difference: 120 Watts (150%)

Memory Bandwidth

In theory, the Radeon HD 7950 3GB is 369% quicker than the Radeon HD 4770 overall, due to its higher bandwidth. (explain)

Radeon HD 7950 3GB		240000 MB/sec
Radeon HD 4770		51200 MB/sec
	Difference: 188800 (369%)

Texel Rate

The Radeon HD 7950 3GB should be quite a bit (approximately 273%) more effective at texture filtering than the Radeon HD 4770. (explain)

Radeon HD 7950 3GB		89600 Mtexels/sec
Radeon HD 4770		24000 Mtexels/sec
	Difference: 65600 (273%)

Pixel Rate

The Radeon HD 7950 3GB is much (about 113%) more effective at full screen anti-aliasing than the Radeon HD 4770, and will be capable of handling higher screen resolutions without losing too much performance. (explain)

Radeon HD 7950 3GB		25600 Mpixels/sec
Radeon HD 4770		12000 Mpixels/sec
	Difference: 13600 (113%)

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 maximum amount of data (measured in megabytes per second) that can be transferred across the external memory interface in a second. It is worked out by multiplying the interface width by its memory speed. If it uses DDR type memory, it should be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The higher the card's memory bandwidth, the faster the card will be in general. It especially helps with AA, HDR and high resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that are processed in one second. This figure is calculated by multiplying the total amount of texture units 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 in a second.

Pixel Rate: Pixel rate is the most pixels that the graphics chip could possibly write to its local memory in one second - measured in millions of pixels per second. The figure is worked out by multiplying the number of 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, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to get to the max fill rate.