Radeon HD 4650 1GB vs Radeon HD 4870 1GB

Intro

Compare all of that to the Radeon HD 4870 1GB, which has a core clock speed of 750 MHz and a GDDR5 memory frequency of 900 MHz. It also features a 256-bit bus, and uses a 55 nm design. It is made up of 800(160x5) SPUs, 40 Texture Address Units, and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4650 1GB		55 Watts
Radeon HD 4870 1GB		150 Watts
	Difference: 95 Watts (173%)

Memory Bandwidth

The Radeon HD 4870 1GB, in theory, should be quite a bit faster than the Radeon HD 4650 1GB overall. (explain)

Radeon HD 4870 1GB		115200 MB/sec
Radeon HD 4650 1GB		22400 MB/sec
	Difference: 92800 (414%)

Texel Rate

The Radeon HD 4870 1GB should be much (about 56%) better at AF than the Radeon HD 4650 1GB. (explain)

Radeon HD 4870 1GB		30000 Mtexels/sec
Radeon HD 4650 1GB		19200 Mtexels/sec
	Difference: 10800 (56%)

Pixel Rate

If running with high levels of AA is important to you, then the Radeon HD 4870 1GB is a better choice, by far. (explain)

Radeon HD 4870 1GB		12000 Mpixels/sec
Radeon HD 4650 1GB		4800 Mpixels/sec
	Difference: 7200 (150%)

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 information (counted in MB per second) that can be transported across the external memory interface within a second. It's calculated by multiplying the bus width by the speed of its memory. In the case of DDR type RAM, 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 is calculated by multiplying the total texture units by the core clock speed of the chip. The higher the texel rate, the better the graphics card will be at handling 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 in a second - measured in millions of pixels per second. The figure is calculated by multiplying the number of Raster Operations Pipelines by the the core clock speed. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel fill rate also depends on lots of other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the ability to reach the max fill rate.