Radeon HD 4870 512MB vs Radeon HD 7790

Intro

Compare that to the Radeon HD 7790, which comes with a core clock frequency of 1000 MHz and a GDDR5 memory speed of 1500 MHz. It also features a 128-bit memory bus, and makes use of a 28 nm design. It is made up of 896 SPUs, 56 TAUs, and 16 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 7790		85 Watts
Radeon HD 4870 512MB		150 Watts
	Difference: 65 Watts (76%)

Memory Bandwidth

As far as performance goes, the Radeon HD 4870 512MB should in theory be just a bit superior to the Radeon HD 7790 overall. (explain)

Radeon HD 4870 512MB		115200 MB/sec
Radeon HD 7790		96000 MB/sec
	Difference: 19200 (20%)

Texel Rate

The Radeon HD 7790 is quite a bit (approximately 87%) better at anisotropic filtering than the Radeon HD 4870 512MB. (explain)

Radeon HD 7790		56000 Mtexels/sec
Radeon HD 4870 512MB		30000 Mtexels/sec
	Difference: 26000 (87%)

Pixel Rate

If running with lots of anti-aliasing is important to you, then the Radeon HD 7790 is the winner, by far. (explain)

Radeon HD 7790		16000 Mpixels/sec
Radeon HD 4870 512MB		12000 Mpixels/sec
	Difference: 4000 (33%)

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 MB per second) that can be transported over the external memory interface in one second. It's calculated by multiplying the bus width by its memory clock speed. In the case of DDR RAM, the result should be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The better the bandwidth is, the better the card will be in general. It especially helps with anti-aliasing, HDR and high resolutions.

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

Pixel Rate: Pixel rate is the maximum number of pixels the graphics card could possibly record to the local memory in a second - measured in millions of pixels per second. The number is worked out by multiplying the number of Render Output Units by the the core speed of the card. 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 rate is also dependant 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 maximum fill rate.