Radeon HD 4850 1GB vs Radeon HD 7950 3GB

Intro

Compare all of that to the Radeon HD 7950 3GB, which features a core clock speed of 800 MHz and a GDDR5 memory frequency of 1250 MHz. It also uses a 384-bit memory bus, and makes use of a 28 nm design. It features 1792 SPUs, 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

As far as performance goes, the Radeon HD 7950 3GB should theoretically be much superior to the Radeon HD 4850 1GB in general. (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 is quite a bit (about 258%) faster with regards to texture filtering 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 will be quite a bit (more or less 156%) better at FSAA than the Radeon HD 4850 1GB, and should be capable of handling higher resolutions without losing too much performance. (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 max amount of information (measured in megabytes per second) that can be moved across the external memory interface in a second. The number is calculated by multiplying the interface width by the speed of its memory. In the case of DDR memory, it must be multiplied by 2 again. If DDR5, multiply by 4 instead. The better the memory bandwidth, the better the card will be in general. It especially helps with AA, High Dynamic Range and high resolutions.

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

Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics chip can possibly write to its local memory per second - measured in millions of pixels per second. The figure is calculated by multiplying the amount of ROPs by the the card's clock speed. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel rate is also dependant on quite a few other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the ability to get to the max fill rate.