Radeon HD 4850 X2 1GB vs Radeon HD 7970

Intro

Compare those specs to the Radeon HD 7970, which uses a 28 nm design. AMD has set the core frequency at 925 MHz. The GDDR5 RAM works at a frequency of 1375 MHz on this card. It features 2048 SPUs along with 128 Texture Address Units and 32 Rasterization Operator Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Both cards have the same power consumption.

Memory Bandwidth

The Radeon HD 7970 should in theory perform quite a bit faster than the Radeon HD 4850 X2 1GB overall. (explain)

Radeon HD 7970		264000 MB/sec
Radeon HD 4850 X2 1GB		127104 MB/sec
	Difference: 136896 (108%)

Texel Rate

The Radeon HD 7970 is much (about 137%) more effective at AF than the Radeon HD 4850 X2 1GB. (explain)

Radeon HD 7970		118400 Mtexels/sec
Radeon HD 4850 X2 1GB		50000 Mtexels/sec
	Difference: 68400 (137%)

Pixel Rate

The Radeon HD 7970 is quite a bit (about 48%) faster with regards to anti-aliasing than the Radeon HD 4850 X2 1GB, and also should be able to handle higher screen resolutions while still performing well. (explain)

Radeon HD 7970		29600 Mpixels/sec
Radeon HD 4850 X2 1GB		20000 Mpixels/sec
	Difference: 9600 (48%)

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 max amount of information (in units of MB per second) that can be moved across the external memory interface within a second. It's calculated by multiplying the interface width by its memory speed. If it uses DDR RAM, it must be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The higher the memory bandwidth, the better the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and high resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that are applied in one second. This figure is worked out by multiplying the total number of texture units by the core speed of the chip. The higher this number, the better the graphics card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied per second.

Pixel Rate: Pixel rate is the maximum amount of pixels the video card could possibly write to its local memory per second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the amount of colour ROPs by the the core speed of the card. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel rate also depends on quite a few other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the ability to reach the maximum fill rate.