Radeon HD 4770 vs Radeon HD 6770

Intro

Compare all that to the Radeon HD 6770, which makes use of a 40 nm design. AMD has clocked the core speed at 900 MHz. The GDDR5 RAM is set to run at a frequency of 1050 MHz on this particular model. 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 4770		80 Watts
Radeon HD 6770		108 Watts
	Difference: 28 Watts (35%)

Memory Bandwidth

The Radeon HD 6770 should in theory be a lot faster than the Radeon HD 4770 overall. (explain)

Radeon HD 6770		67200 MB/sec
Radeon HD 4770		51200 MB/sec
	Difference: 16000 (31%)

Texel Rate

The Radeon HD 6770 should be a lot (approximately 50%) faster with regards to AF than the Radeon HD 4770. (explain)

Radeon HD 6770		36000 Mtexels/sec
Radeon HD 4770		24000 Mtexels/sec
	Difference: 12000 (50%)

Pixel Rate

The Radeon HD 6770 should be just a bit (approximately 20%) more effective at anti-aliasing than the Radeon HD 4770, and able to handle higher resolutions better. (explain)

Radeon HD 6770		14400 Mpixels/sec
Radeon HD 4770		12000 Mpixels/sec
	Difference: 2400 (20%)

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 max amount of data (in units of megabytes per second) that can be moved over the external memory interface in a second. It's worked out by multiplying the card's interface width by the speed of its memory. If it uses DDR type memory, the result should be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The better the card's memory bandwidth, the faster the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and higher screen resolutions.

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

Pixel Rate: Pixel rate is the maximum amount of pixels the graphics card can possibly record to the local memory per second - measured in millions of pixels per second. The figure is calculated by multiplying the amount of colour ROPs by the the card's clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel fill rate also depends on quite a few other factors, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to reach the maximum fill rate.