GeForce 8800 GT 256MB vs Radeon HD 4770

Intro

Compare that to the Radeon HD 4770, which comes with GPU clock speed of 750 MHz, and 512 MB of GDDR5 memory set to run at 800 MHz through a 128-bit bus. It also features 640(128x5) Stream Processors, 32 TAUs, and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4770		80 Watts
GeForce 8800 GT 256MB		105 Watts
	Difference: 25 Watts (31%)

Memory Bandwidth

As far as performance goes, the Radeon HD 4770 should in theory be a small bit superior to the GeForce 8800 GT 256MB overall. (explain)

Radeon HD 4770		51200 MB/sec
GeForce 8800 GT 256MB		44800 MB/sec
	Difference: 6400 (14%)

Texel Rate

The GeForce 8800 GT 256MB will be quite a bit (about 40%) more effective at AF than the Radeon HD 4770. (explain)

GeForce 8800 GT 256MB		33600 Mtexels/sec
Radeon HD 4770		24000 Mtexels/sec
	Difference: 9600 (40%)

Pixel Rate

The Radeon HD 4770 will be much (about 25%) faster with regards to full screen anti-aliasing than the GeForce 8800 GT 256MB, and will be capable of handling higher resolutions without losing too much performance. (explain)

Radeon HD 4770		12000 Mpixels/sec
GeForce 8800 GT 256MB		9600 Mpixels/sec
	Difference: 2400 (25%)

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

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that are applied in one second. This is worked out 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 processed per second.

Pixel Rate: Pixel rate is the maximum number of pixels that the graphics card can possibly record to the local memory in one second - measured in millions of pixels per second. The number is worked out by multiplying the number of colour ROPs 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 lots of other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to reach the max fill rate.