Radeon HD 4650 512MB vs Radeon HD 6850

Intro

Compare those specifications to the Radeon HD 6850, which comes with GPU clock speed of 775 MHz, and 1024 MB of GDDR5 RAM set to run at 1000 MHz through a 256-bit bus. It also is made up of 960 SPUs, 48 Texture Address Units, and 32 Raster Operation Units.

Display Graphs

Hide Graphs

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4650 512MB		55 Watts
Radeon HD 6850		127 Watts
	Difference: 72 Watts (131%)

Memory Bandwidth

Theoretically, the Radeon HD 6850 should be quite a bit faster than the Radeon HD 4650 512MB overall. (explain)

Radeon HD 6850		128000 MB/sec
Radeon HD 4650 512MB		16000 MB/sec
	Difference: 112000 (700%)

Texel Rate

The Radeon HD 6850 will be a lot (more or less 94%) more effective at AF than the Radeon HD 4650 512MB. (explain)

Radeon HD 6850		37200 Mtexels/sec
Radeon HD 4650 512MB		19200 Mtexels/sec
	Difference: 18000 (94%)

Pixel Rate

The Radeon HD 6850 is quite a bit (more or less 417%) better at FSAA than the Radeon HD 4650 512MB, and able to handle higher resolutions more effectively. (explain)

Radeon HD 6850		24800 Mpixels/sec
Radeon HD 4650 512MB		4800 Mpixels/sec
	Difference: 20000 (417%)

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 maximum amount of information (counted in MB per second) that can be moved past the external memory interface within a second. It's calculated by multiplying the interface width by the speed of its memory. In the case of DDR type RAM, 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 AA, High Dynamic Range and higher screen resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that can be applied 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 processed per second.

Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics card could possibly record to the local memory in a second - measured in millions of pixels per second. The number is calculated by multiplying the number of colour ROPs by the the card's clock speed. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel fill rate also depends on many other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the potential to get to the max fill rate.