Radeon HD 4650 1GB vs Radeon HD 7770

Intro

Compare those specs to the Radeon HD 7770, which has clock speeds of 1000 MHz on the GPU, and 1125 MHz on the 1024 MB of GDDR5 RAM. It features 640 SPUs as well as 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 7770		80 Watts
	Difference: 25 Watts (45%)

Memory Bandwidth

In theory, the Radeon HD 7770 should be 221% faster than the Radeon HD 4650 1GB overall, due to its higher data rate. (explain)

Radeon HD 7770		72000 MB/sec
Radeon HD 4650 1GB		22400 MB/sec
	Difference: 49600 (221%)

Texel Rate

The Radeon HD 7770 will be much (more or less 108%) better at texture filtering than the Radeon HD 4650 1GB. (explain)

Radeon HD 7770		40000 Mtexels/sec
Radeon HD 4650 1GB		19200 Mtexels/sec
	Difference: 20800 (108%)

Pixel Rate

If running with a high resolution is important to you, then the Radeon HD 7770 is a better choice, by a large margin. (explain)

Radeon HD 7770		16000 Mpixels/sec
Radeon HD 4650 1GB		4800 Mpixels/sec
	Difference: 11200 (233%)

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 (measured in megabytes per second) that can be transported past the external memory interface within a second. The number is calculated by multiplying the card's bus width by its memory clock speed. If the card has DDR type memory, it should be multiplied by 2 once again. If DDR5, multiply by ANOTHER 2x. The higher 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 texture map elements (texels) that can be applied in one second. This figure is calculated by multiplying the total texture units of the card by the core speed of the chip. The higher the texel rate, 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 number of pixels the graphics card could possibly record to its local memory in one second - measured in millions of pixels per second. The number is calculated by multiplying the number of Render Output Units by the clock speed of the card. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for outputting the pixels (image) to the screen. 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 ability to get to the maximum fill rate.