Radeon HD 4850 2GB vs Radeon HD 7790

Intro

Compare those specs to the Radeon HD 7790, which comes with a clock speed of 1000 MHz and a GDDR5 memory frequency of 1500 MHz. It also features a 128-bit memory bus, and makes use of 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 2GB		110 Watts
	Difference: 25 Watts (29%)

Memory Bandwidth

As far as performance goes, the Radeon HD 7790 should theoretically be much superior to the Radeon HD 4850 2GB overall. (explain)

Radeon HD 7790		96000 MB/sec
Radeon HD 4850 2GB		63552 MB/sec
	Difference: 32448 (51%)

Texel Rate

The Radeon HD 7790 should be much (about 124%) better at texture filtering than the Radeon HD 4850 2GB. (explain)

Radeon HD 7790		56000 Mtexels/sec
Radeon HD 4850 2GB		25000 Mtexels/sec
	Difference: 31000 (124%)

Pixel Rate

If using lots of anti-aliasing is important to you, then the Radeon HD 7790 is superior to the Radeon HD 4850 2GB, and very much so. (explain)

Radeon HD 7790		16000 Mpixels/sec
Radeon HD 4850 2GB		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 max amount of information (counted in megabytes per second) that can be transported across the external memory interface in a second. The number is worked out by multiplying the card's interface width by its memory speed. If the card has DDR type memory, it should be multiplied by 2 again. If DDR5, multiply by 4 instead. The better the card's 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 texture map elements (texels) that are processed per second. This number is calculated by multiplying the total texture units by the core speed of the chip. The higher this number, the better the card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels in one second.

Pixel Rate: Pixel rate is the maximum number of pixels the video card can possibly record to its local memory in a second - measured in millions of pixels per second. The figure is calculated by multiplying the amount of Render Output Units by the the core clock speed. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel output rate also depends on many other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the potential to get to the maximum fill rate.