Radeon HD 4850 X2 512MB vs Radeon HD 7790

Intro

Compare all of that to the Radeon HD 7790, which features a core clock speed of 1000 MHz and a GDDR5 memory speed of 1500 MHz. It also uses a 128-bit bus, and uses a 28 nm design. It features 896 SPUs, 56 TAUs, and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 7790		85 Watts
Radeon HD 4850 X2 512MB		250 Watts
	Difference: 165 Watts (194%)

Memory Bandwidth

Theoretically speaking, the Radeon HD 4850 X2 512MB should be much faster than the Radeon HD 7790 overall. (explain)

Radeon HD 4850 X2 512MB		127104 MB/sec
Radeon HD 7790		96000 MB/sec
	Difference: 31104 (32%)

Texel Rate

The Radeon HD 7790 should be a small bit (about 12%) better at anisotropic filtering than the Radeon HD 4850 X2 512MB. (explain)

Radeon HD 7790		56000 Mtexels/sec
Radeon HD 4850 X2 512MB		50000 Mtexels/sec
	Difference: 6000 (12%)

Pixel Rate

The Radeon HD 4850 X2 512MB should be a lot (approximately 25%) more effective at full screen anti-aliasing than the Radeon HD 7790, and also will be able to handle higher screen resolutions without losing too much performance. (explain)

Radeon HD 4850 X2 512MB		20000 Mpixels/sec
Radeon HD 7790		16000 Mpixels/sec
	Difference: 4000 (25%)

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: Bandwidth is the max amount of data (in units of MB per second) that can be transported across the external memory interface within a second. The number is calculated by multiplying the card's interface width by its memory speed. In the case of DDR type memory, the result should be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The higher the bandwidth is, 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 are applied per second. This figure is worked out by multiplying the total amount of texture units of the card by the core clock speed of the chip. The better the texel rate, the better the graphics 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 most pixels that the graphics chip can possibly write to its local memory in one second - measured in millions of pixels per second. The figure is calculated by multiplying the number of Render Output Units by the the card's clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel output rate is also dependant on lots of other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to reach the maximum fill rate.