Radeon HD 4650 1GB vs Radeon HD 6850

Intro

Compare those specs to the Radeon HD 6850, which features GPU clock speed of 775 MHz, and 1024 MB of GDDR5 memory running 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 1GB		55 Watts
Radeon HD 6850		127 Watts
	Difference: 72 Watts (131%)

Memory Bandwidth

Theoretically speaking, the Radeon HD 6850 should be much faster than the Radeon HD 4650 1GB overall. (explain)

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

Texel Rate

The Radeon HD 6850 is quite a bit (more or less 94%) faster with regards to 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

If running with high levels of AA is important to you, then the Radeon HD 6850 is superior to the Radeon HD 4650 1GB, and very much so. (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 largest amount of data (counted in MB per second) that can be moved across the external memory interface within a second. The number is calculated by multiplying the card's bus width by the speed of its memory. If it uses DDR RAM, it should be multiplied by 2 once again. If DDR5, multiply by 4 instead. The better the bandwidth is, 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 number of texture map elements (texels) that are applied per second. This number is worked out by multiplying the total texture units by the core clock speed of the chip. The higher the texel rate, the better the video card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in one second.

Pixel Rate: Pixel rate is the maximum number of pixels the graphics card can possibly record to the local memory in a second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the amount of Raster Operations Pipelines 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 output rate is also dependant on lots of other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the potential to reach the maximum fill rate.