Radeon HD 4790 vs Radeon HD 6750

Intro

Compare all that to the Radeon HD 6750, which has a GPU core clock speed of 725 MHz, and 512 MB of GDDR5 memory set to run at 1000 MHz through a 128-bit bus. It also is comprised of 720 SPUs, 36 Texture Address Units, and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Memory Bandwidth

As far as performance goes, the Radeon HD 4790 should in theory be quite a bit superior to the Radeon HD 6750 in general. (explain)

Radeon HD 4790		102400 MB/sec
Radeon HD 6750		64000 MB/sec
	Difference: 38400 (60%)

Texel Rate

The Radeon HD 6750 should be quite a bit (about 36%) more effective at AF than the Radeon HD 4790. (explain)

Radeon HD 6750		26100 Mtexels/sec
Radeon HD 4790		19200 Mtexels/sec
	Difference: 6900 (36%)

Pixel Rate

The Radeon HD 6750 will be much (approximately 21%) faster with regards to anti-aliasing than the Radeon HD 4790, and able to handle higher resolutions more effectively. (explain)

Radeon HD 6750		11600 Mpixels/sec
Radeon HD 4790		9600 Mpixels/sec
	Difference: 2000 (21%)

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 data (in units of MB per second) that can be transferred past the external memory interface within a second. It's calculated by multiplying the card's bus width by its memory clock speed. In the case of DDR type 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, HDR and high resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that are processed in one second. This 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 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 maximum amount of pixels the video card can possibly record to the local memory in one second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the amount of colour ROPs 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 also depends on many other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the potential to reach the maximum fill rate.