Radeon HD 4870 1GB vs Radeon HD 5850

Intro

Compare that to the Radeon HD 5850, which makes use of a 40 nm design. AMD has set the core speed at 725 MHz. The GDDR5 RAM works at a speed of 1000 MHz on this particular model. It features 1440(288x5) SPUs along with 72 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 4870 1GB		150 Watts
Radeon HD 5850		151 Watts
	Difference: 1 Watts (1%)

Memory Bandwidth

The Radeon HD 5850 should theoretically perform a bit faster than 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 is much (about 74%) better 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

If using lots of anti-aliasing 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 maximum amount of data (in units of MB per second) that can be moved past the external memory interface in a second. It is calculated by multiplying the card's bus width by the speed of its memory. If the card has DDR memory, it must be multiplied by 2 once again. If DDR5, multiply by 4 instead. The higher the memory bandwidth, the faster the card will be in general. It especially helps with AA, High Dynamic Range and high resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that can be processed in one second. This number is calculated by multiplying the total number of texture units by the core clock speed of the chip. The better the texel rate, the better the graphics card will be at 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 that the graphics chip can possibly write to its local memory in one second - measured in millions of pixels per second. Pixel rate 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 outputting the pixels (image) to the screen. The actual pixel fill rate also depends on lots of other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to get to the max fill rate.