Radeon HD 4870 1GB vs Radeon HD 7870

Intro

Compare that to the Radeon HD 7870, which features GPU clock speed of 1000 MHz, and 2048 MB of GDDR5 RAM set to run at 1200 MHz through a 256-bit bus. It also is comprised of 1280 Stream Processors, 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 1GB		150 Watts
Radeon HD 7870		175 Watts
	Difference: 25 Watts (17%)

Memory Bandwidth

As far as performance goes, the Radeon HD 7870 should in theory be a lot superior to the Radeon HD 4870 1GB in general. (explain)

Radeon HD 7870		153600 MB/sec
Radeon HD 4870 1GB		115200 MB/sec
	Difference: 38400 (33%)

Texel Rate

The Radeon HD 7870 should be quite a bit (approximately 167%) more effective at anisotropic filtering than the Radeon HD 4870 1GB. (explain)

Radeon HD 7870		80000 Mtexels/sec
Radeon HD 4870 1GB		30000 Mtexels/sec
	Difference: 50000 (167%)

Pixel Rate

If running with a high resolution is important to you, then the Radeon HD 7870 is the winner, and very much so. (explain)

Radeon HD 7870		32000 Mpixels/sec
Radeon HD 4870 1GB		12000 Mpixels/sec
	Difference: 20000 (167%)

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 data (counted in MB per second) that can be moved past the external memory interface in one second. It is worked out by multiplying the card's interface width by its memory speed. If the card has DDR memory, the result should be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The better 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 amount of texture map elements (texels) that can be applied in one 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 this number, the better the graphics card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in a second.

Pixel Rate: Pixel rate is the maximum number of pixels that the graphics card can possibly write to the local memory in one second - measured in millions of pixels per second. The number is worked out by multiplying the number of colour ROPs by the the core speed of the card. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel rate is also dependant on quite a few other factors, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to reach the maximum fill rate.