Radeon HD 4850 512MB vs Radeon HD 7790

Intro

Compare those specs to the Radeon HD 7790, which has a clock frequency of 1000 MHz and a GDDR5 memory speed of 1500 MHz. It also features a 128-bit bus, and uses a 28 nm design. It is comprised of 896 SPUs, 56 Texture Address Units, and 16 ROPs.

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

As far as performance goes, the Radeon HD 7790 should theoretically be a lot better than the Radeon HD 4850 512MB overall. (explain)

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

Texel Rate

The Radeon HD 7790 should be quite a bit (more or less 124%) more effective at texture filtering 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 is much (more or less 60%) faster with regards to anti-aliasing than the Radeon HD 4850 512MB, and also able to handle higher screen resolutions without slowing down too much. (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: Bandwidth is the maximum amount of data (in units of megabytes per second) that can be moved past the external memory interface in a second. The number is worked out by multiplying the card's bus width by the speed of its memory. If it uses DDR type RAM, the result should be multiplied by 2 once 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 anti-aliasing, High Dynamic Range and high resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that can be applied in one second. This number is calculated by multiplying the total texture units of the card by the core clock speed of the chip. The higher the texel rate, the better the 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 maximum amount of pixels the video card can possibly record to the local memory in one second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the number of colour ROPs by the the core clock speed. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel output 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 reach the max fill rate.