Radeon HD 4870 1GB vs Radeon HD 5850

Intro

Compare those specifications to the Radeon HD 5850, which comes with GPU clock speed of 725 MHz, and 1024 MB of GDDR5 RAM set to run at 1000 MHz through a 256-bit bus. It also is made up of 1440(288x5) SPUs, 72 Texture Address Units, and 32 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4870 1GB		150 Watts
Radeon HD 5850		151 Watts
	Difference: 1 Watts (1%)

Memory Bandwidth

The Radeon HD 5850 should theoretically be a small bit faster than the Radeon HD 4870 1GB in general. (explain)

Radeon HD 5850		128000 MB/sec
Radeon HD 4870 1GB		115200 MB/sec
	Difference: 12800 (11%)

Texel Rate

The Radeon HD 5850 is quite a bit (more or less 74%) faster with regards to anisotropic filtering than the Radeon HD 4870 1GB. (explain)

Radeon HD 5850		52200 Mtexels/sec
Radeon HD 4870 1GB		30000 Mtexels/sec
	Difference: 22200 (74%)

Pixel Rate

If using lots of anti-aliasing is important to you, then the Radeon HD 5850 is the winner, by far. (explain)

Radeon HD 5850		23200 Mpixels/sec
Radeon HD 4870 1GB		12000 Mpixels/sec
	Difference: 11200 (93%)

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 largest amount of information (in units of MB per second) that can be transported past the external memory interface in one second. It's calculated by multiplying the bus width by the speed of its memory. If the card has DDR type RAM, it should be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The better the bandwidth is, the better the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and higher screen resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that can be applied per second. This number is calculated by multiplying the total texture units by the core speed of the chip. The better the texel rate, the better the 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 amount of pixels that the graphics chip could possibly record to its local memory in one second - measured in millions of pixels per second. The number is worked out by multiplying the number of Render Output Units by the clock speed of the card. 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 rate is also dependant on lots of other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to get to the max fill rate.