Radeon HD 4670 1GB vs Radeon HD 6790

Intro

Compare those specs to the Radeon HD 6790, which features a GPU core clock speed of 840 MHz, and 1024 MB of GDDR5 memory set to run at 1050 MHz through a 256-bit bus. It also is comprised of 800 SPUs, 40 TAUs, and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4670 1GB		70 Watts
Radeon HD 6790		150 Watts
	Difference: 80 Watts (114%)

Memory Bandwidth

Theoretically speaking, the Radeon HD 6790 is 282% quicker than the Radeon HD 4670 1GB in general, due to its greater data rate. (explain)

Radeon HD 6790		134400 MB/sec
Radeon HD 4670 1GB		35200 MB/sec
	Difference: 99200 (282%)

Texel Rate

The Radeon HD 6790 is a lot (more or less 40%) more effective at anisotropic filtering than the Radeon HD 4670 1GB. (explain)

Radeon HD 6790		33600 Mtexels/sec
Radeon HD 4670 1GB		24000 Mtexels/sec
	Difference: 9600 (40%)

Pixel Rate

If running with lots of anti-aliasing is important to you, then the Radeon HD 6790 is the winner, by far. (explain)

Radeon HD 6790		13440 Mpixels/sec
Radeon HD 4670 1GB		6000 Mpixels/sec
	Difference: 7440 (124%)

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 (in units of megabytes per second) that can be transferred across the external memory interface within a second. The number is calculated by multiplying the bus width by its memory speed. If the card has DDR type memory, the result should be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The higher the bandwidth is, the better 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 is worked out by multiplying the total amount of texture units by the core speed of the chip. The higher this number, the better the graphics card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied per second.

Pixel Rate: Pixel rate is the maximum number of pixels that the graphics card can possibly write to the local memory in one second - measured in millions of pixels per second. The figure is worked out by multiplying the number of Render Output Units by the clock speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel fill rate also depends on lots of other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to get to the maximum fill rate.