Radeon HD 4850 X2 512MB vs Radeon HD 7990

Intro

Compare those specifications to the Radeon HD 7990, which makes use of a 28 nm design. AMD has clocked the core frequency at 950 MHz. The GDDR5 memory works at a frequency of 1500 MHz on this particular model. It features 2048 SPUs along with 128 TAUs and 32 Rasterization Operator Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4850 X2 512MB		250 Watts
Radeon HD 7990		375 Watts
	Difference: 125 Watts (50%)

Memory Bandwidth

As far as performance goes, the Radeon HD 7990 should theoretically be a lot superior to the Radeon HD 4850 X2 512MB in general. (explain)

Radeon HD 7990		576000 MB/sec
Radeon HD 4850 X2 512MB		127104 MB/sec
	Difference: 448896 (353%)

Texel Rate

The Radeon HD 7990 will be quite a bit (about 386%) more effective at anisotropic filtering than the Radeon HD 4850 X2 512MB. (explain)

Radeon HD 7990		243200 Mtexels/sec
Radeon HD 4850 X2 512MB		50000 Mtexels/sec
	Difference: 193200 (386%)

Pixel Rate

The Radeon HD 7990 should be much (about 204%) more effective at anti-aliasing than the Radeon HD 4850 X2 512MB, and also will be capable of handling higher resolutions without losing too much performance. (explain)

Radeon HD 7990		60800 Mpixels/sec
Radeon HD 4850 X2 512MB		20000 Mpixels/sec
	Difference: 40800 (204%)

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 maximum amount of information (counted in megabytes per second) that can be transferred across the external memory interface within a second. The number is calculated by multiplying the interface width by its memory speed. If it uses DDR RAM, it should be multiplied by 2 again. If DDR5, multiply by 4 instead. The higher the memory bandwidth, the better the card will be in general. It especially helps with anti-aliasing, HDR and higher screen resolutions.

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

Pixel Rate: Pixel rate is the maximum amount of pixels the video card could possibly record to its local memory in a second - measured in millions of pixels per second. The number is worked out by multiplying the number of Render Output Units by the the card's clock speed. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel output rate also depends on many other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to get to the maximum fill rate.