Radeon HD 4650 1GB vs Radeon HD 6850

Intro

Compare all that to the Radeon HD 6850, which features a core clock frequency of 775 MHz and a GDDR5 memory frequency of 1000 MHz. It also features a 256-bit memory bus, and uses a 40 nm design. It is comprised of 960 SPUs, 48 TAUs, and 32 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4650 1GB		55 Watts
Radeon HD 6850		127 Watts
	Difference: 72 Watts (131%)

Memory Bandwidth

The Radeon HD 6850 should in theory be a lot faster than the Radeon HD 4650 1GB in general. (explain)

Radeon HD 6850		128000 MB/sec
Radeon HD 4650 1GB		22400 MB/sec
	Difference: 105600 (471%)

Texel Rate

The Radeon HD 6850 is much (about 94%) more effective at AF than the Radeon HD 4650 1GB. (explain)

Radeon HD 6850		37200 Mtexels/sec
Radeon HD 4650 1GB		19200 Mtexels/sec
	Difference: 18000 (94%)

Pixel Rate

The Radeon HD 6850 will be quite a bit (more or less 417%) better at full screen anti-aliasing than the Radeon HD 4650 1GB, and will be capable of handling higher screen resolutions without slowing down too much. (explain)

Radeon HD 6850		24800 Mpixels/sec
Radeon HD 4650 1GB		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: Memory bandwidth is the maximum amount of data (counted in MB per second) that can be transported past the external memory interface in one second. It is worked out by multiplying the interface width by the speed of its memory. In the case of DDR RAM, the result should be multiplied by 2 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 per 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 card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed in one second.

Pixel Rate: Pixel rate is the most pixels the graphics card could possibly record to the local memory in one second - measured in millions of pixels per second. The number is worked out by multiplying the amount of Render Output Units by the the core clock speed. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel rate is also dependant on quite a few other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to reach the maximum fill rate.