Radeon HD 4890 2GB vs Radeon HD 6770

Intro

Compare all of that to the Radeon HD 6770, which has core clock speeds of 900 MHz on the GPU, and 1050 MHz on the 512 MB of GDDR5 RAM. It features 800 SPUs as well as 40 TAUs and 16 Rasterization Operator Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 6770		108 Watts
Radeon HD 4890 2GB		190 Watts
	Difference: 82 Watts (76%)

Memory Bandwidth

The Radeon HD 4890 2GB, in theory, should perform much faster than the Radeon HD 6770 in general. (explain)

Radeon HD 4890 2GB		124800 MB/sec
Radeon HD 6770		67200 MB/sec
	Difference: 57600 (86%)

Texel Rate

The Radeon HD 4890 2GB will be a bit (approximately 11%) faster with regards to AF than the Radeon HD 6770. (explain)

Radeon HD 4890 2GB		40000 Mtexels/sec
Radeon HD 6770		36000 Mtexels/sec
	Difference: 4000 (11%)

Pixel Rate

The Radeon HD 4890 2GB should be a bit (approximately 11%) better at full screen anti-aliasing than the Radeon HD 6770, and also able to handle higher resolutions more effectively. (explain)

Radeon HD 4890 2GB		16000 Mpixels/sec
Radeon HD 6770		14400 Mpixels/sec
	Difference: 1600 (11%)

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 maximum amount of data (in units of MB per second) that can be transferred across the external memory interface in one second. It's calculated by multiplying the interface width by its memory clock speed. If the card has DDR memory, the result should be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The better the memory bandwidth, the faster the card will be in general. It especially helps with AA, HDR and higher screen resolutions.

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

Pixel Rate: Pixel rate is the maximum number of pixels that the graphics chip could possibly record to the local memory per second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the amount of Raster Operations Pipelines by the the card's clock speed. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel fill rate is also dependant on quite a few other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the potential to get to the maximum fill rate.