Radeon HD 4870 512MB vs Radeon HD 5850

Intro

Compare those specs to the Radeon HD 5850, which makes use of a 40 nm design. AMD has clocked the core speed at 725 MHz. The GDDR5 RAM is set to run at a speed of 1000 MHz on this model. It features 1440(288x5) SPUs along with 72 TAUs and 32 Rasterization Operator 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

In theory, the Radeon HD 5850 will be 11% faster than the Radeon HD 4870 512MB overall, due to 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 a lot (about 74%) faster with regards to 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

The Radeon HD 5850 will be quite a bit (approximately 93%) more effective at full screen anti-aliasing than the Radeon HD 4870 512MB, and will be able to handle higher resolutions more effectively. (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: Bandwidth is the max amount of data (in units of megabytes per second) that can be moved across the external memory interface in a second. It's worked out by multiplying the card's bus width by its memory speed. If it uses DDR type memory, the result should be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The better the bandwidth is, the faster 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 texture map elements (texels) that can be processed per second. This figure is worked out by multiplying the total amount of texture units of the card by the core speed of the chip. The higher the texel rate, the better the graphics 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 graphics card can possibly write to the local memory in one second - measured in millions of pixels per second. The number is calculated by multiplying the amount of ROPs by the clock speed of the card. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel rate also depends on many other factors, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to reach the maximum fill rate.