Radeon HD 4650 1GB vs Radeon HD 6770 1GB

Intro

Compare that to the Radeon HD 6770 1GB, which comes with core clock speeds of 900 MHz on the GPU, and 1050 MHz on the 1024 MB of GDDR5 RAM. It features 800 SPUs along with 40 Texture Address Units and 16 Rasterization Operator Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4650 1GB		55 Watts
Radeon HD 6770 1GB		108 Watts
	Difference: 53 Watts (96%)

Memory Bandwidth

Theoretically speaking, the Radeon HD 6770 1GB should be a lot faster than the Radeon HD 4650 1GB overall. (explain)

Radeon HD 6770 1GB		67200 MB/sec
Radeon HD 4650 1GB		22400 MB/sec
	Difference: 44800 (200%)

Texel Rate

The Radeon HD 6770 1GB is much (more or less 88%) faster with regards to anisotropic filtering than the Radeon HD 4650 1GB. (explain)

Radeon HD 6770 1GB		36000 Mtexels/sec
Radeon HD 4650 1GB		19200 Mtexels/sec
	Difference: 16800 (88%)

Pixel Rate

If running with lots of anti-aliasing is important to you, then the Radeon HD 6770 1GB is superior to the Radeon HD 4650 1GB, by far. (explain)

Radeon HD 6770 1GB		14400 Mpixels/sec
Radeon HD 4650 1GB		4800 Mpixels/sec
	Difference: 9600 (200%)

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 (counted in MB per second) that can be moved past the external memory interface in one second. It's worked out by multiplying the interface width by its memory clock speed. In the case of DDR memory, the result should be multiplied by 2 again. If DDR5, multiply by 4 instead. The higher the memory bandwidth, 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 are applied in one second. This figure is calculated by multiplying the total amount of texture units by the core clock speed of the chip. The higher the texel rate, the better the graphics card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels in one second.

Pixel Rate: Pixel rate is the maximum number of pixels the video card can possibly record to the local memory per second - measured in millions of pixels per second. The number is calculated by multiplying the number of colour ROPs by the the core speed of the card. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel rate also depends on lots of other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the ability to reach the max fill rate.