Radeon HD 4890 1GB vs Radeon HD 7850

Intro

Compare those specs to the Radeon HD 7850, which features GPU core speed of 860 MHz, and 2048 MB of GDDR5 memory running at 1200 MHz through a 256-bit bus. It also features 1024 SPUs, 64 Texture Address Units, and 32 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 7850		130 Watts
Radeon HD 4890 1GB		190 Watts
	Difference: 60 Watts (46%)

Memory Bandwidth

As far as performance goes, the Radeon HD 7850 should theoretically be a lot superior to the Radeon HD 4890 1GB overall. (explain)

Radeon HD 7850		153600 MB/sec
Radeon HD 4890 1GB		124800 MB/sec
	Difference: 28800 (23%)

Texel Rate

The Radeon HD 7850 will be much (about 38%) more effective at AF than the Radeon HD 4890 1GB. (explain)

Radeon HD 7850		55040 Mtexels/sec
Radeon HD 4890 1GB		40000 Mtexels/sec
	Difference: 15040 (38%)

Pixel Rate

The Radeon HD 7850 should be a lot (more or less 72%) faster with regards to FSAA than the Radeon HD 4890 1GB, and also capable of handling higher resolutions more effectively. (explain)

Radeon HD 7850		27520 Mpixels/sec
Radeon HD 4890 1GB		16000 Mpixels/sec
	Difference: 11520 (72%)

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 (in units of megabytes per second) that can be transported over the external memory interface in a second. The number is calculated by multiplying the card's interface width by its memory speed. If it uses DDR type RAM, the result should be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The better the memory bandwidth, the faster the card will be in general. It especially helps with AA, High Dynamic Range and high 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 better the texel rate, the better the card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in one second.

Pixel Rate: Pixel rate is the most pixels that the graphics chip can possibly write to its local memory per second - measured in millions of pixels per second. The number is calculated by multiplying the number of Raster Operations Pipelines by the the card's clock speed. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel output rate is also dependant on quite a few 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.