Radeon HD 4870 512MB vs Radeon HD 5850

Intro

Compare those specs to the Radeon HD 5850, which has a clock frequency of 725 MHz and a GDDR5 memory frequency of 1000 MHz. It also features a 256-bit memory bus, and makes use of a 40 nm design. It is made up of 1440(288x5) SPUs, 72 TAUs, and 32 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4870 512MB		150 Watts
Radeon HD 5850		151 Watts
	Difference: 1 Watts (1%)

Memory Bandwidth

Theoretically speaking, the Radeon HD 5850 is 11% faster than the Radeon HD 4870 512MB overall, because of its higher data rate. (explain)

Radeon HD 5850		128000 MB/sec
Radeon HD 4870 512MB		115200 MB/sec
	Difference: 12800 (11%)

Texel Rate

The Radeon HD 5850 should be quite a bit (approximately 74%) more effective at AF than the Radeon HD 4870 512MB. (explain)

Radeon HD 5850		52200 Mtexels/sec
Radeon HD 4870 512MB		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 512MB		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 data (counted in MB per second) that can be transported across the external memory interface within a second. It is worked out by multiplying the interface width by its memory clock speed. If it uses DDR type RAM, it must be multiplied by 2 once again. If it uses DDR5, multiply by ANOTHER 2x. The better the card's memory bandwidth, the better the card will be in general. It especially helps with AA, HDR and higher screen resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that can be applied in one second. This number 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 applied per second.

Pixel Rate: Pixel rate is the most pixels that the graphics card could possibly write to the local memory in a second - measured in millions of pixels per second. The figure is worked out by multiplying the amount 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 many other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to reach the max fill rate.