Radeon HD 3690/3830 vs Radeon HD 4650 1GB

Intro

Compare all of that to the Radeon HD 4650 1GB, which has a GPU core clock speed of 600 MHz, and 1024 MB of GDDR3 RAM running at 700 MHz through a 128-bit bus. It also features 320(64x5) SPUs, 32 TAUs, and 8 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4650 1GB		55 Watts
Radeon HD 3690/3830		75 Watts
	Difference: 20 Watts (36%)

Memory Bandwidth

Performance-wise, the Radeon HD 3690/3830 should theoretically be a small bit better than the Radeon HD 4650 1GB overall. (explain)

Radeon HD 3690/3830		26496 MB/sec
Radeon HD 4650 1GB		22400 MB/sec
	Difference: 4096 (18%)

Texel Rate

The Radeon HD 4650 1GB should be much (approximately 80%) faster with regards to anisotropic filtering than the Radeon HD 3690/3830. (explain)

Radeon HD 4650 1GB		19200 Mtexels/sec
Radeon HD 3690/3830		10688 Mtexels/sec
	Difference: 8512 (80%)

Pixel Rate

The Radeon HD 3690/3830 will be much (more or less 123%) more effective at full screen anti-aliasing than the Radeon HD 4650 1GB, and also should be able to handle higher resolutions more effectively. (explain)

Radeon HD 3690/3830		10688 Mpixels/sec
Radeon HD 4650 1GB		4800 Mpixels/sec
	Difference: 5888 (123%)

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 largest amount of information (counted in megabytes per second) that can be moved across the external memory interface in a second. The number is calculated by multiplying the card's interface width by its memory speed. If it uses DDR type memory, the result should be multiplied by 2 once again. If it uses DDR5, multiply by ANOTHER 2x. The better the memory bandwidth, the faster the card will be in general. It especially helps with AA, HDR and higher screen resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that are processed in one second. This figure is calculated by multiplying the total number of texture units by the core clock speed of the chip. The higher this number, the better the video 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 maximum amount of pixels that the graphics card could possibly record to the local memory per second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the amount of Render Output Units by the the core speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel rate also depends on lots of other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the potential to get to the maximum fill rate.