Radeon HD 4850 1GB vs Radeon HD 7950 3GB

Intro

Compare that to the Radeon HD 7950 3GB, which uses a 28 nm design. AMD has clocked the core frequency at 800 MHz. The GDDR5 memory is set to run at a frequency of 1250 MHz on this particular card. It features 1792 SPUs along with 112 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 7950 3GB		200 Watts
	Difference: 90 Watts (82%)

Memory Bandwidth

In theory, the Radeon HD 7950 3GB should be 278% quicker than the Radeon HD 4850 1GB in general, due to its greater data rate. (explain)

Radeon HD 7950 3GB		240000 MB/sec
Radeon HD 4850 1GB		63552 MB/sec
	Difference: 176448 (278%)

Texel Rate

The Radeon HD 7950 3GB will be quite a bit (about 258%) better at AF than the Radeon HD 4850 1GB. (explain)

Radeon HD 7950 3GB		89600 Mtexels/sec
Radeon HD 4850 1GB		25000 Mtexels/sec
	Difference: 64600 (258%)

Pixel Rate

The Radeon HD 7950 3GB should be much (approximately 156%) faster with regards to FSAA than the Radeon HD 4850 1GB, and will be able to handle higher resolutions while still performing well. (explain)

Radeon HD 7950 3GB		25600 Mpixels/sec
Radeon HD 4850 1GB		10000 Mpixels/sec
	Difference: 15600 (156%)

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 largest amount of information (in units of MB per second) that can be moved past the external memory interface within a second. It is calculated by multiplying the interface width by its memory speed. If the card has DDR type RAM, it must be multiplied by 2 once 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 high resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that are applied in one second. This figure is worked out by multiplying the total texture units of the card by the core speed of the chip. The higher the texel rate, the better the graphics card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed per second.

Pixel Rate: Pixel rate is the most pixels the graphics card 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 Render Output Units by the the core speed of the card. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel rate also depends on lots of other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to get to the maximum fill rate.