Radeon HD 4870 1GB vs Radeon HD 5850

Intro

Compare those specifications to the Radeon HD 5850, which has core clock speeds of 725 MHz on the GPU, and 1000 MHz on the 1024 MB of GDDR5 RAM. It features 1440(288x5) SPUs along with 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

In theory, the Radeon HD 5850 should perform just a 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 should be quite a bit (about 74%) more effective at texture 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

The Radeon HD 5850 should be much (approximately 93%) more effective at anti-aliasing than the Radeon HD 4870 1GB, and capable of handling higher screen resolutions while still performing well. (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 transported across the external memory interface within a second. It is calculated by multiplying the card's bus width by its memory speed. If it uses DDR memory, it must be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The better the card's memory bandwidth, the faster the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and high resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that are processed in one second. This figure is calculated by multiplying the total amount of texture units of the card by the core clock 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 one second.

Pixel Rate: Pixel rate is the maximum amount of pixels the video card could possibly record to its local memory in one second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the amount of ROPs by the the card's clock speed. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel output rate also depends on quite a few other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to get to the maximum fill rate.