Radeon HD 4850 X2 1GB vs Radeon HD 7870

Intro

Compare all of that to the Radeon HD 7870, which comes with a GPU core clock speed of 1000 MHz, and 2048 MB of GDDR5 RAM running at 1200 MHz through a 256-bit bus. It also features 1280 Stream Processors, 80 Texture Address Units, and 32 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 7870		175 Watts
Radeon HD 4850 X2 1GB		250 Watts
	Difference: 75 Watts (43%)

Memory Bandwidth

Theoretically speaking, the Radeon HD 7870 will be 21% faster than the Radeon HD 4850 X2 1GB overall, because of its higher bandwidth. (explain)

Radeon HD 7870		153600 MB/sec
Radeon HD 4850 X2 1GB		127104 MB/sec
	Difference: 26496 (21%)

Texel Rate

The Radeon HD 7870 is a lot (approximately 60%) better at AF than the Radeon HD 4850 X2 1GB. (explain)

Radeon HD 7870		80000 Mtexels/sec
Radeon HD 4850 X2 1GB		50000 Mtexels/sec
	Difference: 30000 (60%)

Pixel Rate

If running with lots of anti-aliasing is important to you, then the Radeon HD 7870 is superior to the Radeon HD 4850 X2 1GB, by a large margin. (explain)

Radeon HD 7870		32000 Mpixels/sec
Radeon HD 4850 X2 1GB		20000 Mpixels/sec
	Difference: 12000 (60%)

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 maximum amount of information (in units of MB per second) that can be transferred past the external memory interface within a second. It is worked out by multiplying the card's interface width by its memory speed. In the case of DDR RAM, it must be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The higher the bandwidth is, the faster the card will be in general. It especially helps with anti-aliasing, HDR and higher screen resolutions.

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

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