Radeon HD 4850 512MB vs Radeon HD 7870

Intro

Compare all of that to the Radeon HD 7870, which has GPU clock speed of 1000 MHz, and 2048 MB of GDDR5 memory running at 1200 MHz through a 256-bit bus. It also is comprised of 1280 SPUs, 80 TAUs, and 32 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4850 512MB		110 Watts
Radeon HD 7870		175 Watts
	Difference: 65 Watts (59%)

Memory Bandwidth

Theoretically, the Radeon HD 7870 should be quite a bit faster than the Radeon HD 4850 512MB overall. (explain)

Radeon HD 7870		153600 MB/sec
Radeon HD 4850 512MB		63552 MB/sec
	Difference: 90048 (142%)

Texel Rate

The Radeon HD 7870 will be a lot (more or less 220%) better at AF than the Radeon HD 4850 512MB. (explain)

Radeon HD 7870		80000 Mtexels/sec
Radeon HD 4850 512MB		25000 Mtexels/sec
	Difference: 55000 (220%)

Pixel Rate

The Radeon HD 7870 should be much (about 220%) better at AA than the Radeon HD 4850 512MB, and should be able to handle higher screen resolutions without losing too much performance. (explain)

Radeon HD 7870		32000 Mpixels/sec
Radeon HD 4850 512MB		10000 Mpixels/sec
	Difference: 22000 (220%)

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.

Price Comparison

Specifications

Memory Bandwidth: Bandwidth is the maximum amount of data (counted in megabytes per second) that can be moved past the external memory interface in one second. It is worked out by multiplying the interface width by the speed of its memory. If the card has DDR type memory, it must be multiplied by 2 again. If DDR5, multiply by 4 instead. The higher the memory bandwidth, the faster the card will be in general. It especially helps with AA, HDR and high resolutions.

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

Pixel Rate: Pixel rate is the most pixels that the graphics chip can possibly write to the local memory in one second - measured in millions of pixels per second. The number is worked out by multiplying the number of Raster Operations Pipelines by the the core clock speed. 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 output rate is also dependant on lots of other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to reach the maximum fill rate.