Radeon HD 4870 X2 vs Radeon HD 7750

Intro

Compare those specs to the Radeon HD 7750, which features GPU core speed of 800 MHz, and 1024 MB of GDDR5 RAM set to run at 1125 MHz through a 128-bit bus. It also features 512 Stream Processors, 32 TAUs, and 16 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 7750		55 Watts
Radeon HD 4870 X2		350 Watts
	Difference: 295 Watts (536%)

Memory Bandwidth

In theory, the Radeon HD 4870 X2 should be 220% faster than the Radeon HD 7750 in general, due to its greater bandwidth. (explain)

Radeon HD 4870 X2		230400 MB/sec
Radeon HD 7750		72000 MB/sec
	Difference: 158400 (220%)

Texel Rate

The Radeon HD 4870 X2 is much (about 134%) better at anisotropic filtering than the Radeon HD 7750. (explain)

Radeon HD 4870 X2		60000 Mtexels/sec
Radeon HD 7750		25600 Mtexels/sec
	Difference: 34400 (134%)

Pixel Rate

If using lots of anti-aliasing is important to you, then the Radeon HD 4870 X2 is the winner, and very much so. (explain)

Radeon HD 4870 X2		24000 Mpixels/sec
Radeon HD 7750		12800 Mpixels/sec
	Difference: 11200 (88%)

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 information (in units of MB per second) that can be transported past the external memory interface in a second. It is worked out by multiplying the card's interface width by its memory clock speed. In the case of DDR type RAM, it must be multiplied by 2 once again. If DDR5, multiply by ANOTHER 2x. The higher 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 number of texture map elements (texels) that can be processed in one second. This figure is calculated by multiplying the total amount of texture units of the card by the core speed of the chip. The higher this number, the better the video card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in a second.

Pixel Rate: Pixel rate is the maximum number of pixels the graphics card can possibly write to its local memory in a second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the amount of ROPs by the the core clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel fill rate also depends on many other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to get to the maximum fill rate.