GeForce 8800 GT 256MB vs Radeon HD 7770

Intro

Compare all of that to the Radeon HD 7770, which makes use of a 28 nm design. AMD has clocked the core speed at 1000 MHz. The GDDR5 RAM works at a speed of 1125 MHz on this card. It features 640 SPUs along with 40 TAUs and 16 Rasterization Operator Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 7770		80 Watts
GeForce 8800 GT 256MB		105 Watts
	Difference: 25 Watts (31%)

Memory Bandwidth

The Radeon HD 7770, in theory, should be quite a bit faster than the GeForce 8800 GT 256MB overall. (explain)

Radeon HD 7770		72000 MB/sec
GeForce 8800 GT 256MB		44800 MB/sec
	Difference: 27200 (61%)

Texel Rate

The Radeon HD 7770 will be a bit (about 19%) more effective at AF than the GeForce 8800 GT 256MB. (explain)

Radeon HD 7770		40000 Mtexels/sec
GeForce 8800 GT 256MB		33600 Mtexels/sec
	Difference: 6400 (19%)

Pixel Rate

The Radeon HD 7770 will be quite a bit (approximately 67%) faster with regards to anti-aliasing than the GeForce 8800 GT 256MB, and also will be able to handle higher resolutions without slowing down too much. (explain)

Radeon HD 7770		16000 Mpixels/sec
GeForce 8800 GT 256MB		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: Memory bandwidth is the largest amount of data (counted in megabytes per second) that can be transferred past the external memory interface in a second. The number is worked out by multiplying the bus width by the speed of its memory. If it uses DDR type RAM, the result should be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The higher the bandwidth is, the better the card will be in general. It especially helps with AA, HDR and higher screen resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that can be applied per second. This figure is calculated by multiplying the total number of texture units of the card by the core 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 processed in a second.

Pixel Rate: Pixel rate is the most pixels the video card can possibly record to its local memory per second - measured in millions of pixels per second. The figure is worked out by multiplying the number of Render Output Units by the the card's clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel fill rate is also dependant on quite a few other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the ability to get to the maximum fill rate.