Radeon HD 4850 1GB vs Radeon HD 5870

Intro

Compare those specifications to the Radeon HD 5870, which features a clock frequency of 850 MHz and a GDDR5 memory speed of 1200 MHz. It also uses a 256-bit bus, and makes use of a 40 nm design. It is made up of 1600(320x5) SPUs, 80 TAUs, and 32 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4850 1GB		110 Watts
Radeon HD 5870		188 Watts
	Difference: 78 Watts (71%)

Memory Bandwidth

As far as performance goes, the Radeon HD 5870 should in theory be a lot superior to the Radeon HD 4850 1GB overall. (explain)

Radeon HD 5870		153600 MB/sec
Radeon HD 4850 1GB		63552 MB/sec
	Difference: 90048 (142%)

Texel Rate

The Radeon HD 5870 is much (more or less 172%) more effective at anisotropic filtering than the Radeon HD 4850 1GB. (explain)

Radeon HD 5870		68000 Mtexels/sec
Radeon HD 4850 1GB		25000 Mtexels/sec
	Difference: 43000 (172%)

Pixel Rate

The Radeon HD 5870 is quite a bit (approximately 172%) better at anti-aliasing than the Radeon HD 4850 1GB, and also should be able to handle higher resolutions while still performing well. (explain)

Radeon HD 5870		27200 Mpixels/sec
Radeon HD 4850 1GB		10000 Mpixels/sec
	Difference: 17200 (172%)

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 largest amount of information (measured in megabytes per second) that can be moved over the external memory interface in a second. It is calculated by multiplying the card's interface width by its memory clock speed. If it uses DDR type RAM, it must be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The higher the memory bandwidth, 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 processed in one second. This is worked out by multiplying the total texture units of the card by the core clock speed of the chip. The better this number, the better the video card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed in a second.

Pixel Rate: Pixel rate is the maximum number of pixels that the graphics chip can possibly write to the local memory in one second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the number of Raster Operations Pipelines by the the core speed of the card. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel fill rate is also dependant on lots of 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.