Radeon HD 4870 2GB vs Radeon HD 7990

Intro

Compare those specs to the Radeon HD 7990, which features GPU core speed of 950 MHz, and 3072 MB of GDDR5 memory running at 1500 MHz through a 384-bit bus. It also is made up of 2048 Stream Processors, 128 Texture Address Units, and 32 Raster Operation Units.

Display Graphs

Hide Graphs

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4870 2GB		150 Watts
Radeon HD 7990		375 Watts
	Difference: 225 Watts (150%)

Memory Bandwidth

In theory, the Radeon HD 7990 will be 400% quicker than the Radeon HD 4870 2GB in general, because of its greater data rate. (explain)

Radeon HD 7990		576000 MB/sec
Radeon HD 4870 2GB		115200 MB/sec
	Difference: 460800 (400%)

Texel Rate

The Radeon HD 7990 will be a lot (more or less 711%) more effective at texture filtering than the Radeon HD 4870 2GB. (explain)

Radeon HD 7990		243200 Mtexels/sec
Radeon HD 4870 2GB		30000 Mtexels/sec
	Difference: 213200 (711%)

Pixel Rate

If running with high levels of AA is important to you, then the Radeon HD 7990 is superior to the Radeon HD 4870 2GB, and very much so. (explain)

Radeon HD 7990		60800 Mpixels/sec
Radeon HD 4870 2GB		12000 Mpixels/sec
	Difference: 48800 (407%)

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.

One or more cards in this comparison are multi-core. This means that their bandwidth, texel and pixel rates are theoretically doubled - this does not mean the card will actually perform twice as fast, but only that it should in theory be able to. Actual game benchmarks will give a more accurate idea of what it's capable of.

Price Comparison

Specifications

Memory Bandwidth: Bandwidth is the max amount of data (measured in MB per second) that can be transported past the external memory interface within a second. It's calculated by multiplying the bus width by its memory clock speed. In the case of DDR memory, it should be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The better the bandwidth is, the faster the card will be in general. It especially helps with anti-aliasing, HDR and higher screen resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that are applied per second. This is calculated by multiplying the total number of 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 handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels per second.

Pixel Rate: Pixel rate is the maximum amount of pixels the graphics card could possibly record to the 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 clock speed of the card. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel output rate is also dependant on lots of other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to reach the max fill rate.