Radeon HD 4670 1GB vs Radeon HD 6770 1GB

Intro

Compare all of that to the Radeon HD 6770 1GB, which has a clock speed of 900 MHz and a GDDR5 memory frequency of 1050 MHz. It also makes use of a 128-bit memory bus, and makes use of a 40 nm design. It is comprised of 800 SPUs, 40 TAUs, and 16 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4670 1GB		70 Watts
Radeon HD 6770 1GB		108 Watts
	Difference: 38 Watts (54%)

Memory Bandwidth

Theoretically speaking, the Radeon HD 6770 1GB will be 91% quicker than the Radeon HD 4670 1GB overall, because of its greater bandwidth. (explain)

Radeon HD 6770 1GB		67200 MB/sec
Radeon HD 4670 1GB		35200 MB/sec
	Difference: 32000 (91%)

Texel Rate

The Radeon HD 6770 1GB is quite a bit (about 50%) better at texture filtering than the Radeon HD 4670 1GB. (explain)

Radeon HD 6770 1GB		36000 Mtexels/sec
Radeon HD 4670 1GB		24000 Mtexels/sec
	Difference: 12000 (50%)

Pixel Rate

The Radeon HD 6770 1GB will be much (more or less 140%) better at full screen anti-aliasing than the Radeon HD 4670 1GB, and should be capable of handling higher screen resolutions better. (explain)

Radeon HD 6770 1GB		14400 Mpixels/sec
Radeon HD 4670 1GB		6000 Mpixels/sec
	Difference: 8400 (140%)

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 data (in units of megabytes per second) that can be moved across the external memory interface within a second. It is worked out by multiplying the card's interface width by its memory speed. If the card has DDR type memory, it must be multiplied by 2 again. If DDR5, multiply by 4 instead. The higher the memory bandwidth, the faster the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and high resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that can be processed per second. This is calculated by multiplying the total number of texture units by the core clock speed of the chip. The higher this number, the better the video card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels in one 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 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 filling the screen with pixels (the image). The actual pixel output rate is also dependant on lots of other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the potential to reach the max fill rate.