Radeon HD 4750 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 features 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

Theoretically, the Radeon HD 6790 should be quite a bit faster than the Radeon HD 4750 in general. (explain)

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

Texel Rate

The Radeon HD 6790 will be much (more or less 44%) better at anisotropic filtering than the Radeon HD 4750. (explain)

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

Pixel Rate

If running with high levels of AA is important to you, then the Radeon HD 6790 is a better choice, but only just. (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: Memory bandwidth is the largest amount of information (counted in MB per second) that can be transferred past the external memory interface in one second. It is worked out by multiplying the interface width by its memory speed. If the card has DDR memory, it should be multiplied by 2 once again. If it uses DDR5, multiply by ANOTHER 2x. The higher the card's memory bandwidth, the better the card will be in general. It especially helps with AA, High Dynamic Range and high resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that can be applied per second. This number is calculated by multiplying the total amount of texture units 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 processed in one second.

Pixel Rate: Pixel rate is the maximum number of pixels that the graphics chip could possibly record to the local memory in a second - measured in millions of pixels per second. The number is calculated by multiplying the amount of colour ROPs by the the core speed of the card. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel rate is also dependant on lots of other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to get to the max fill rate.