Radeon HD 4850 512MB vs Radeon HD 7790

Intro

Compare those specifications to the Radeon HD 7790, which makes use of a 28 nm design. AMD has clocked the core frequency at 1000 MHz. The GDDR5 memory is set to run at a speed of 1500 MHz on this model. It features 896 SPUs along with 56 TAUs and 16 Rasterization Operator Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 7790		85 Watts
Radeon HD 4850 512MB		110 Watts
	Difference: 25 Watts (29%)

Memory Bandwidth

The Radeon HD 7790, in theory, should be quite a bit faster than the Radeon HD 4850 512MB in general. (explain)

Radeon HD 7790		96000 MB/sec
Radeon HD 4850 512MB		63552 MB/sec
	Difference: 32448 (51%)

Texel Rate

The Radeon HD 7790 is a lot (more or less 124%) better at AF than the Radeon HD 4850 512MB. (explain)

Radeon HD 7790		56000 Mtexels/sec
Radeon HD 4850 512MB		25000 Mtexels/sec
	Difference: 31000 (124%)

Pixel Rate

The Radeon HD 7790 will be a lot (about 60%) more effective at FSAA than the Radeon HD 4850 512MB, and also able to handle higher resolutions while still performing well. (explain)

Radeon HD 7790		16000 Mpixels/sec
Radeon HD 4850 512MB		10000 Mpixels/sec
	Difference: 6000 (60%)

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 maximum amount of data (in units of MB per second) that can be transported across the external memory interface within a second. It is calculated by multiplying the card's interface width by the speed of its memory. If it uses DDR memory, it should be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The better the card's memory bandwidth, the better the card will be in general. It especially helps with AA, HDR and high resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that can be applied in one second. This figure is calculated by multiplying the total number of texture units of the card by the core speed of the chip. The higher this number, the better the video 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 maximum amount 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 calculated by multiplying the amount of Render Output Units by the the card's clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel fill rate also depends on many other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to get to the maximum fill rate.