Radeon HD 4650 1GB vs Radeon HD 6770

Intro

Compare those specs to the Radeon HD 6770, which has a GPU core clock speed of 900 MHz, and 512 MB of GDDR5 memory set to run at 1050 MHz through a 128-bit bus. It also is comprised of 800 Stream Processors, 40 Texture Address Units, and 16 Raster Operation 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 theoretically be quite a bit better than the Radeon HD 4650 1GB overall. (explain)

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

Texel Rate

The Radeon HD 6770 should be quite a bit (approximately 88%) better at 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

The Radeon HD 6770 will be much (about 200%) better at FSAA than the Radeon HD 4650 1GB, and also should be capable of handling higher resolutions more effectively. (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: Bandwidth is the largest amount of data (counted in megabytes per second) that can be moved past the external memory interface in a second. It is calculated by multiplying the interface width by its memory clock speed. If the card has DDR RAM, it should be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The better the bandwidth is, the better the card will be in general. It especially helps with AA, HDR 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 of the card by the core speed of the chip. The better this number, the better the video 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 write to its local memory per second - measured in millions of pixels per second. The figure is calculated by multiplying the number of colour ROPs by the the core clock speed. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel fill rate also depends on quite a few other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the potential to get to the maximum fill rate.