Radeon HD 4850 X2 512MB vs Radeon HD 6790

Intro

Compare all of that to the Radeon HD 6790, which makes use of a 40 nm design. AMD has clocked the core frequency at 840 MHz. The GDDR5 RAM runs at a speed of 1050 MHz on this particular model. It features 800 SPUs along with 40 Texture Address Units and 16 Rasterization Operator Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 6790		150 Watts
Radeon HD 4850 X2 512MB		250 Watts
	Difference: 100 Watts (67%)

Memory Bandwidth

Theoretically speaking, the Radeon HD 6790 should be a bit faster than the Radeon HD 4850 X2 512MB overall. (explain)

Radeon HD 6790		134400 MB/sec
Radeon HD 4850 X2 512MB		127104 MB/sec
	Difference: 7296 (6%)

Texel Rate

The Radeon HD 4850 X2 512MB will be a lot (about 49%) faster with regards to anisotropic filtering than the Radeon HD 6790. (explain)

Radeon HD 4850 X2 512MB		50000 Mtexels/sec
Radeon HD 6790		33600 Mtexels/sec
	Difference: 16400 (49%)

Pixel Rate

If using a high resolution is important to you, then the Radeon HD 4850 X2 512MB is the winner, by far. (explain)

Radeon HD 4850 X2 512MB		20000 Mpixels/sec
Radeon HD 6790		13440 Mpixels/sec
	Difference: 6560 (49%)

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.

One or more cards in this comparison are multi-core. This means that their bandwidth, texel and pixel rates are theoretically doubled - this does not mean the card will actually perform twice as fast, but only that it should in theory be able to. Actual game benchmarks will give a more accurate idea of what it's capable of.

Price Comparison

Specifications

Memory Bandwidth: Memory bandwidth is the largest amount of data (measured in MB per second) that can be transferred past the external memory interface within a second. The number is calculated by multiplying the card's interface width by the speed of its memory. If the card has DDR RAM, 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 anti-aliasing, HDR and high resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that can be processed in one second. This is calculated by multiplying the total texture units of the card by the core speed of the chip. The higher the texel rate, the better the graphics 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 that the graphics card could possibly record to its local memory in a second - measured in millions of pixels per second. The figure is calculated by multiplying the amount of ROPs by the clock speed of the card. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel rate is also dependant on lots of other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the ability to reach the maximum fill rate.