Radeon HD 4650 1GB vs Radeon HD 6870

Intro

Compare those specs to the Radeon HD 6870, which makes use of a 40 nm design. AMD has set the core frequency at 900 MHz. The GDDR5 memory works at a speed of 1050 MHz on this model. It features 1120 SPUs along with 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 1GB		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 1GB in general. (explain)

Radeon HD 6870		134400 MB/sec
Radeon HD 4650 1GB		22400 MB/sec
	Difference: 112000 (500%)

Texel Rate

The Radeon HD 6870 will be a lot (more or less 163%) better at texture filtering than the Radeon HD 4650 1GB. (explain)

Radeon HD 6870		50400 Mtexels/sec
Radeon HD 4650 1GB		19200 Mtexels/sec
	Difference: 31200 (163%)

Pixel Rate

The Radeon HD 6870 should be quite a bit (about 500%) better at anti-aliasing than the Radeon HD 4650 1GB, and should be able to handle higher resolutions while still performing well. (explain)

Radeon HD 6870		28800 Mpixels/sec
Radeon HD 4650 1GB		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: Memory bandwidth is the max amount of information (measured in megabytes per second) that can be transferred over the external memory interface within a second. It is worked out by multiplying the card's bus width by its memory speed. If it uses DDR memory, it must be multiplied by 2 once again. If it uses DDR5, multiply by ANOTHER 2x. The higher the bandwidth is, the better the card will be in general. It especially helps with anti-aliasing, HDR and higher screen resolutions.

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

Pixel Rate: Pixel rate is the most pixels the graphics card can possibly write to its local memory in one second - measured in millions of pixels per second. The number is calculated by multiplying the number of ROPs by the the card's clock speed. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel rate also depends on quite a few other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to reach the maximum fill rate.