Radeon HD 4850 1GB vs Radeon HD 7870

Intro

Compare all that to the Radeon HD 7870, which comes with core speeds of 1000 MHz on the GPU, and 1200 MHz on the 2048 MB of GDDR5 memory. It features 1280 SPUs as well as 80 Texture Address Units and 32 Rasterization Operator Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4850 1GB		110 Watts
Radeon HD 7870		175 Watts
	Difference: 65 Watts (59%)

Memory Bandwidth

The Radeon HD 7870 should theoretically perform a lot faster than the Radeon HD 4850 1GB overall. (explain)

Radeon HD 7870		153600 MB/sec
Radeon HD 4850 1GB		63552 MB/sec
	Difference: 90048 (142%)

Texel Rate

The Radeon HD 7870 should be a lot (approximately 220%) faster with regards to texture filtering than the Radeon HD 4850 1GB. (explain)

Radeon HD 7870		80000 Mtexels/sec
Radeon HD 4850 1GB		25000 Mtexels/sec
	Difference: 55000 (220%)

Pixel Rate

If using lots of anti-aliasing is important to you, then the Radeon HD 7870 is the winner, and very much so. (explain)

Radeon HD 7870		32000 Mpixels/sec
Radeon HD 4850 1GB		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: Memory bandwidth is the maximum amount of data (counted in megabytes per second) that can be moved across the external memory interface in a second. The number is calculated by multiplying the bus width by the speed of its memory. If it uses DDR RAM, the result should be multiplied by 2 again. If DDR5, multiply by 4 instead. The higher the card's memory bandwidth, the faster the card will be in general. It especially helps with AA, HDR and higher screen resolutions.

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

Pixel Rate: Pixel rate is the maximum number of pixels the graphics card can possibly write to the local memory per second - measured in millions of pixels per second. The figure is worked out by multiplying the number of Render Output Units by the clock speed of the card. ROPs (Raster Operations Pipelines - also sometimes called 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.