Radeon HD 4870 1GB vs Radeon HD 4870 X2

Intro

Compare that to the Radeon HD 4870 X2, which features clock speeds of 750 MHz on the GPU, and 900 MHz on the 1024 MB of GDDR5 RAM. It features 800(160x5) SPUs along with 40 TAUs and 16 Rasterization Operator Units.

Display Graphs

Hide Graphs

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4870 1GB		150 Watts
Radeon HD 4870 X2		350 Watts
	Difference: 200 Watts (133%)

Memory Bandwidth

Performance-wise, the Radeon HD 4870 X2 should theoretically be quite a bit superior to the Radeon HD 4870 1GB overall. (explain)

Radeon HD 4870 X2		230400 MB/sec
Radeon HD 4870 1GB		115200 MB/sec
	Difference: 115200 (100%)

Texel Rate

The Radeon HD 4870 X2 should be a lot (about 100%) better at anisotropic filtering than the Radeon HD 4870 1GB. (explain)

Radeon HD 4870 X2		60000 Mtexels/sec
Radeon HD 4870 1GB		30000 Mtexels/sec
	Difference: 30000 (100%)

Pixel Rate

The Radeon HD 4870 X2 is much (approximately 100%) faster with regards to anti-aliasing than the Radeon HD 4870 1GB, and also capable of handling higher screen resolutions more effectively. (explain)

Radeon HD 4870 X2		24000 Mpixels/sec
Radeon HD 4870 1GB		12000 Mpixels/sec
	Difference: 12000 (100%)

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 maximum amount of information (in units of MB per second) that can be transferred past the external memory interface in one second. It is calculated by multiplying the card's interface width by its memory speed. In the case of DDR type RAM, the result should be multiplied by 2 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 AA, High Dynamic Range and high resolutions.

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

Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics card could possibly write to the local memory in a second - measured in millions of pixels per second. The number is worked out by multiplying the number of ROPs by the clock speed of the card. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel output rate is also dependant on many other factors, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to reach the max fill rate.