Radeon HD 4550 256MB vs Radeon HD 7870

Intro

Compare that to the Radeon HD 7870, which uses a 28 nm design. AMD has clocked the core frequency at 1000 MHz. The GDDR5 memory is set to run at a frequency of 1200 MHz on this card. It features 1280 SPUs along with 80 Texture Address Units and 32 Rasterization Operator Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4550 256MB		25 Watts
Radeon HD 7870		175 Watts
	Difference: 150 Watts (600%)

Memory Bandwidth

In theory, the Radeon HD 7870 should be 1100% faster than the Radeon HD 4550 256MB overall, because of its greater bandwidth. (explain)

Radeon HD 7870		153600 MB/sec
Radeon HD 4550 256MB		12800 MB/sec
	Difference: 140800 (1100%)

Texel Rate

The Radeon HD 7870 is much (about 1567%) more effective at AF than the Radeon HD 4550 256MB. (explain)

Radeon HD 7870		80000 Mtexels/sec
Radeon HD 4550 256MB		4800 Mtexels/sec
	Difference: 75200 (1567%)

Pixel Rate

The Radeon HD 7870 is quite a bit (more or less 1233%) faster with regards to FSAA than the Radeon HD 4550 256MB, and also will be capable of handling higher resolutions without losing too much performance. (explain)

Radeon HD 7870		32000 Mpixels/sec
Radeon HD 4550 256MB		2400 Mpixels/sec
	Difference: 29600 (1233%)

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 (measured in megabytes per second) that can be transported past the external memory interface within a second. It is worked out by multiplying the interface width by its memory clock speed. In the case of DDR RAM, the result should be multiplied by 2 again. If DDR5, multiply by 4 instead. The better the bandwidth is, the faster the card will be in general. It especially helps with anti-aliasing, 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 is calculated by multiplying the total texture units of the card by the core speed of the chip. The higher this number, the better the graphics card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels per second.

Pixel Rate: Pixel rate is the maximum number of pixels the video card could possibly write to its local memory in a second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the number of ROPs by the the core speed of the card. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel output rate is also dependant on quite a few other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the potential to reach the max fill rate.