Radeon HD 4870 1GB vs Radeon HD 5850

Intro

Compare all that to the Radeon HD 5850, which features clock speeds of 725 MHz on the GPU, and 1000 MHz on the 1024 MB of GDDR5 memory. It features 1440(288x5) SPUs as well as 72 Texture Address Units and 32 ROPs.

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

As far as performance goes, the Radeon HD 5850 should in theory be a small bit superior to the Radeon HD 4870 1GB overall. (explain)

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

Texel Rate

The Radeon HD 5850 will be quite a bit (approximately 74%) faster with regards to AF 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 running with a high screen resolution is important to you, then the Radeon HD 5850 is a better choice, 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 max amount of information (measured in megabytes per second) that can be transferred across the external memory interface in a second. It's worked out by multiplying the bus width by its memory clock speed. If it uses DDR type memory, it should be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The higher the bandwidth is, 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 texture map elements (texels) that can be processed in one second. This is worked out by multiplying the total amount of texture units 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 one second.

Pixel Rate: Pixel rate is the most pixels the video card could possibly record to its local memory per second - measured in millions of pixels per second. The number is worked out by multiplying the amount of ROPs by the the core speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel fill rate also depends on many other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to get to the max fill rate.