Radeon HD 4650 1GB vs Radeon HD 6770

Intro

Compare those specs to the Radeon HD 6770, which comes with core speeds of 900 MHz on the GPU, and 1050 MHz on the 512 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		108 Watts
	Difference: 53 Watts (96%)

Memory Bandwidth

As far as performance goes, the Radeon HD 6770 should in theory be much superior to the Radeon HD 4650 1GB in general. (explain)

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

Texel Rate

The Radeon HD 6770 is a lot (approximately 88%) faster with regards to anisotropic filtering than the Radeon HD 4650 1GB. (explain)

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

Pixel Rate

If running with a high screen resolution is important to you, then the Radeon HD 6770 is superior to the Radeon HD 4650 1GB, and very much so. (explain)

Radeon HD 6770		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 max amount of information (measured in megabytes per second) that can be moved over the external memory interface within a second. It is calculated by multiplying the interface width by its memory speed. If it uses DDR RAM, it should be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The better the card's memory bandwidth, the faster the card will be in general. It especially helps with AA, High Dynamic Range and high resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that can be applied in one second. This is calculated by multiplying the total amount of texture units by the core clock 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 processed in a second.

Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics card could possibly record to the local memory in one second - measured in millions of pixels per second. The number is calculated by multiplying the amount of Render Output Units by the the core 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, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to reach the maximum fill rate.