Radeon HD 3690/3830 vs Radeon HD 4670 512MB

Intro

Compare that to the Radeon HD 4670 512MB, which has a GPU core clock speed of 750 MHz, and 512 MB of GDDR4/GDDR3/DDR3/DDR2 memory set to run at 1000 MHz through a 128-bit bus. It also is comprised of 320(64x5) SPUs, 32 Texture Address Units, and 8 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4670 512MB		70 Watts
Radeon HD 3690/3830		75 Watts
	Difference: 5 Watts (7%)

Memory Bandwidth

Performance-wise, the Radeon HD 4670 512MB should in theory be quite a bit better than the Radeon HD 3690/3830 in general. (explain)

Radeon HD 4670 512MB		32000 MB/sec
Radeon HD 3690/3830		26496 MB/sec
	Difference: 5504 (21%)

Texel Rate

The Radeon HD 4670 512MB should be quite a bit (about 125%) better at texture filtering than the Radeon HD 3690/3830. (explain)

Radeon HD 4670 512MB		24000 Mtexels/sec
Radeon HD 3690/3830		10688 Mtexels/sec
	Difference: 13312 (125%)

Pixel Rate

The Radeon HD 3690/3830 is quite a bit (approximately 78%) more effective at full screen anti-aliasing than the Radeon HD 4670 512MB, and also able to handle higher resolutions more effectively. (explain)

Radeon HD 3690/3830		10688 Mpixels/sec
Radeon HD 4670 512MB		6000 Mpixels/sec
	Difference: 4688 (78%)

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 largest amount of data (measured in MB per second) that can be transferred over the external memory interface within a second. It's calculated by multiplying the interface width by its memory speed. In the case of DDR RAM, it should be multiplied by 2 again. If DDR5, multiply by 4 instead. The higher the bandwidth is, the faster the card will be in general. It especially helps with AA, High Dynamic Range and higher screen resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that can be processed in one second. This number is worked out by multiplying the total texture units by the core speed of the chip. The higher this number, the better the video card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed in a second.

Pixel Rate: Pixel rate is the most pixels the graphics card could possibly record to its local memory in one second - measured in millions of pixels per second. The number is worked out by multiplying the number of Render Output Units by the the core speed of the card. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel rate is also dependant on many other factors, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to reach the maximum fill rate.