Radeon HD 4790 vs Radeon HD 6670 (OEM) 1GB

Intro

Compare that to the Radeon HD 6670 (OEM) 1GB, which features GPU clock speed of 800 MHz, and 1024 MB of GDDR5 RAM running at 1000 MHz through a 128-bit bus. It also is comprised of 480 SPUs, 24 TAUs, and 8 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Memory Bandwidth

In theory, the Radeon HD 4790 should be 60% quicker than the Radeon HD 6670 (OEM) 1GB in general, due to its greater data rate. (explain)

Radeon HD 4790		102400 MB/sec
Radeon HD 6670 (OEM) 1GB		64000 MB/sec
	Difference: 38400 (60%)

Texel Rate

Both cards have exactly the same texel rate, so in theory they should perform equally good at at anisotropic filtering. (explain)

Pixel Rate

The Radeon HD 4790 should be much (more or less 50%) more effective at full screen anti-aliasing than the Radeon HD 6670 (OEM) 1GB, and also will be capable of handling higher screen resolutions while still performing well. (explain)

Radeon HD 4790		9600 Mpixels/sec
Radeon HD 6670 (OEM) 1GB		6400 Mpixels/sec
	Difference: 3200 (50%)

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 (in units of megabytes per second) that can be transferred past the external memory interface in a second. It is calculated by multiplying the card's interface width by the speed of its memory. If the card has DDR RAM, the result should be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The higher the memory bandwidth, the better 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 are applied in one second. This figure is worked out by multiplying the total number of texture units by the core speed of the chip. The higher the texel rate, the better the card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels in one second.

Pixel Rate: Pixel rate is the most pixels the graphics card could possibly write to the local memory per second - measured in millions of pixels per second. The figure is worked out by multiplying the number of ROPs by the the core clock speed. ROPs (Raster Operations Pipelines - aka 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 of the card - the lower the memory bandwidth is, the lower the ability to reach the maximum fill rate.