Radeon HD 4870 X2 vs Radeon HD 7990

Intro

Compare those specs to the Radeon HD 7990, which has a clock speed of 950 MHz and a GDDR5 memory frequency of 1500 MHz. It also makes use of a 384-bit memory bus, and makes use of a 28 nm design. It is comprised of 2048 SPUs, 128 Texture Address Units, and 32 ROPs.

Display Graphs

Hide Graphs

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4870 X2		350 Watts
Radeon HD 7990		375 Watts
	Difference: 25 Watts (7%)

Memory Bandwidth

The Radeon HD 7990 should in theory be a lot faster than the Radeon HD 4870 X2 in general. (explain)

Radeon HD 7990		576000 MB/sec
Radeon HD 4870 X2		230400 MB/sec
	Difference: 345600 (150%)

Texel Rate

The Radeon HD 7990 is a lot (approximately 305%) better at texture filtering than the Radeon HD 4870 X2. (explain)

Radeon HD 7990		243200 Mtexels/sec
Radeon HD 4870 X2		60000 Mtexels/sec
	Difference: 183200 (305%)

Pixel Rate

The Radeon HD 7990 will be much (more or less 153%) faster with regards to AA than the Radeon HD 4870 X2, and also capable of handling higher screen resolutions while still performing well. (explain)

Radeon HD 7990		60800 Mpixels/sec
Radeon HD 4870 X2		24000 Mpixels/sec
	Difference: 36800 (153%)

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: Memory bandwidth is the maximum amount of data (in units of MB per second) that can be moved past the external memory interface in a second. It's worked out by multiplying the bus width by its memory clock speed. If it uses DDR type memory, the result should be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The higher the card's memory bandwidth, the faster the card will be in general. It especially helps with AA, HDR and higher screen resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that can be applied per second. This figure 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 graphics card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed in one second.

Pixel Rate: Pixel rate is the maximum number of pixels the graphics card could possibly write to its local memory in a second - measured in millions of pixels per second. The number is calculated by multiplying the amount of Render Output Units by the the card's clock speed. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel output rate is also dependant on many other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to reach the maximum fill rate.