Radeon HD 4850 1GB vs Radeon HD 7870

Intro

Compare those specifications to the Radeon HD 7870, which makes use of a 28 nm design. AMD has clocked the core speed at 1000 MHz. The GDDR5 memory runs at a speed of 1200 MHz on this card. 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

In theory, the Radeon HD 7870 will be 142% quicker than the Radeon HD 4850 1GB in general, due to its higher bandwidth. (explain)

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

Texel Rate

The Radeon HD 7870 is much (more or less 220%) more effective at anisotropic 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

The Radeon HD 7870 is a lot (about 220%) better at AA than the Radeon HD 4850 1GB, and also should be able to handle higher resolutions without slowing down too much. (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 information (counted in megabytes per second) that can be moved over the external memory interface in one second. It's worked out by multiplying the bus width by its memory clock speed. If the card has DDR type RAM, it must be multiplied by 2 once again. If it uses 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 number of texture map elements (texels) that are applied in one second. This figure is worked out by multiplying the total texture units by the core clock speed of the chip. The higher this number, the better the graphics card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed in one second.

Pixel Rate: Pixel rate is the most pixels the video card can possibly write to its local memory in one second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the number of colour ROPs by the the card's clock speed. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel output rate is also dependant on lots of other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the ability to reach the maximum fill rate.