Radeon HD 4870 512MB vs Radeon HD 5870

Intro

Compare those specs to the Radeon HD 5870, which has a core clock speed of 850 MHz and a GDDR5 memory speed of 1200 MHz. It also features a 256-bit bus, and makes use of a 40 nm design. It is made up of 1600(320x5) SPUs, 80 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 5870		188 Watts
	Difference: 38 Watts (25%)

Memory Bandwidth

As far as performance goes, the Radeon HD 5870 should theoretically be quite a bit superior to the Radeon HD 4870 512MB overall. (explain)

Radeon HD 5870		153600 MB/sec
Radeon HD 4870 512MB		115200 MB/sec
	Difference: 38400 (33%)

Texel Rate

The Radeon HD 5870 should be much (about 127%) more effective at anisotropic filtering than the Radeon HD 4870 512MB. (explain)

Radeon HD 5870		68000 Mtexels/sec
Radeon HD 4870 512MB		30000 Mtexels/sec
	Difference: 38000 (127%)

Pixel Rate

The Radeon HD 5870 will be much (approximately 127%) better at AA than the Radeon HD 4870 512MB, and should be capable of handling higher resolutions without losing too much performance. (explain)

Radeon HD 5870		27200 Mpixels/sec
Radeon HD 4870 512MB		12000 Mpixels/sec
	Difference: 15200 (127%)

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 data (counted in megabytes per second) that can be transferred over the external memory interface in one second. It's calculated by multiplying the interface width by its memory clock speed. If the card has DDR type memory, it should be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The higher the bandwidth is, the better the card will be in general. It especially helps with anti-aliasing, HDR and high resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that can be applied per second. This 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 video card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels per second.

Pixel Rate: Pixel rate is the maximum number of pixels that the graphics chip could possibly record to its local memory per second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the number of ROPs by the the core clock speed. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel output rate is also dependant on many other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to get to the max fill rate.