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 frequency of 1050 MHz on this particular model. It features 1120 SPUs as well as 56 Texture Address Units and 32 ROPs.

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

Theoretically, the Radeon HD 6870 should be quite a bit faster than the Radeon HD 4650 512MB in general. (explain)

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

Texel Rate

The Radeon HD 6870 will be much (approximately 163%) faster with regards to 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 will be much (more or less 500%) more effective at AA than the Radeon HD 4650 512MB, and will be able to handle higher screen resolutions while still performing well. (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 (measured in MB per second) that can be moved across the external memory interface in one second. It is worked out by multiplying the interface width by its memory speed. If it uses DDR type RAM, the result should be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The better the bandwidth is, the better the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and high resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that are applied per second. This is worked out by multiplying the total amount of texture units of the card by the core clock speed of the chip. The higher the texel rate, the better the graphics card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels per second.

Pixel Rate: Pixel rate is the most pixels the graphics card can possibly write to the local memory per second - measured in millions of pixels per second. The figure is calculated by multiplying the amount of ROPs by the the card's clock speed. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel fill rate also depends on many other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the ability to get to the max fill rate.