Radeon HD 4650 512MB vs Radeon HD 6870

Intro

Compare those specs to the Radeon HD 6870, which makes use of a 40 nm design. AMD has clocked the core frequency at 900 MHz. The GDDR5 memory runs at a speed of 1050 MHz on this model. It features 1120 SPUs as well as 56 TAUs and 32 Rasterization Operator Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4650 512MB		55 Watts
Radeon HD 6870		151 Watts
	Difference: 96 Watts (175%)

Memory Bandwidth

The Radeon HD 6870 should in theory perform much faster than the Radeon HD 4650 512MB overall. (explain)

Radeon HD 6870		134400 MB/sec
Radeon HD 4650 512MB		16000 MB/sec
	Difference: 118400 (740%)

Texel Rate

The Radeon HD 6870 is much (about 163%) better at AF than the Radeon HD 4650 512MB. (explain)

Radeon HD 6870		50400 Mtexels/sec
Radeon HD 4650 512MB		19200 Mtexels/sec
	Difference: 31200 (163%)

Pixel Rate

The Radeon HD 6870 should be much (more or less 500%) more effective at full screen anti-aliasing than the Radeon HD 4650 512MB, and also capable of handling higher screen resolutions without slowing down too much. (explain)

Radeon HD 6870		28800 Mpixels/sec
Radeon HD 4650 512MB		4800 Mpixels/sec
	Difference: 24000 (500%)

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 (in units of MB per second) that can be transported past the external memory interface in one second. The number is calculated by multiplying the card's interface width by its memory speed. If the card has DDR type memory, it must be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The higher the card's memory bandwidth, the better 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 amount of texture map elements (texels) that are processed per second. This number is worked out by multiplying the total texture units by the core clock speed of the chip. The better this number, the better the 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 that the graphics chip can possibly record to its local memory in a second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the number of Render Output Units by the the core 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 ability to reach the max fill rate.