Radeon HD 4750 vs Radeon HD 6790

Intro

Compare all that to the Radeon HD 6790, which features GPU clock speed of 840 MHz, and 1024 MB of GDDR5 memory running at 1050 MHz through a 256-bit bus. It also is made up 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 4750		75 Watts
Radeon HD 6790		150 Watts
	Difference: 75 Watts (100%)

Memory Bandwidth

The Radeon HD 6790 should theoretically perform much faster than the Radeon HD 4750 overall. (explain)

Radeon HD 6790		134400 MB/sec
Radeon HD 4750		51200 MB/sec
	Difference: 83200 (163%)

Texel Rate

The Radeon HD 6790 is quite a bit (approximately 44%) better at AF than the Radeon HD 4750. (explain)

Radeon HD 6790		33600 Mtexels/sec
Radeon HD 4750		23360 Mtexels/sec
	Difference: 10240 (44%)

Pixel Rate

The Radeon HD 6790 will be a bit (approximately 15%) more effective at FSAA than the Radeon HD 4750, and should be capable of handling higher resolutions without losing too much performance. (explain)

Radeon HD 6790		13440 Mpixels/sec
Radeon HD 4750		11680 Mpixels/sec
	Difference: 1760 (15%)

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 max amount of information (counted in MB per second) that can be transported over the external memory interface within a second. It is calculated by multiplying the card's bus width by its memory speed. If it uses DDR type RAM, it must be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The higher the bandwidth is, the faster the card will be in general. It especially helps with anti-aliasing, HDR and high resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that can be applied in one second. This figure is worked out by multiplying the total number of texture units of the card by the core clock 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 in a second.

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