Radeon HD 4870 1GB vs Radeon HD 4870 X2

Intro

Compare all of that to the Radeon HD 4870 X2, which uses a 55 nm design. ATi has clocked the core speed at 750 MHz. The GDDR5 memory runs at a frequency of 900 MHz on this particular model. It features 800(160x5) SPUs along with 40 Texture Address Units and 16 Rasterization Operator Units.

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Settings:	Ultra High Quality
AA:	8x
AF:	none
Resolution:	1920x1200
Test Machine:	Tom's Hardware Test Machine (Source)

Radeon HD 4870 X2		64 FPS
Radeon HD 4870 1GB		33 FPS
	Difference: 31 FPS (94%)

Battlefield Bad Company 2

Settings:	High Quality
AA:	4x
AF:	8x
Resolution:	1920x1200
Test Machine:	Tom's Hardware Test Machine (Source)

Radeon HD 4870 X2		60 FPS
Radeon HD 4870 1GB		33 FPS
	Difference: 27 FPS (82%)

Left4Dead 2

Settings:	Very High
AA:	8x
AF:	16x
Resolution:	1920x1200
Test Machine:	Tom's Hardware Test Machine (Source)

Radeon HD 4870 X2		134 FPS
Radeon HD 4870 1GB		80 FPS
	Difference: 54 FPS (68%)

Supreme Commander 2

Settings:	High
AA:	8x
AF:	16x
Resolution:	1920x1200
Test Machine:	Tom's Hardware Test Machine (Source)

Radeon HD 4870 X2		99 FPS
Radeon HD 4870 1GB		57 FPS
	Difference: 42 FPS (74%)

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Radeon HD 4870 X2 wins

(Based entirely on the benchmarks listed above)

When combining all game benchmark scores on this page together, the Radeon HD 4870 X2 wins overall, by 154 FPS. Please note that we do not have the results of every benchmark ever done for these cards, so the results may differ wildly in different games.

Radeon HD 4870 X2		357 FPS
Radeon HD 4870 1GB		203 FPS
	Difference: 154 FPS (76%)

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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 a lot superior to the Radeon HD 4870 1GB in general. (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 is much (approximately 100%) faster with regards to texture 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 will be quite a bit (approximately 100%) faster with regards to full screen anti-aliasing than the Radeon HD 4870 1GB, and also will be able to handle higher screen resolutions without slowing down too much. (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: Memory bandwidth is the largest amount of data (measured in MB per second) that can be transferred across the external memory interface within a second. It is worked out by multiplying the bus width by the speed of its memory. In the case of DDR memory, it must be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The higher 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 texture map elements (texels) that are applied per second. This is worked out by multiplying the total 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 handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed in a second.

Pixel Rate: Pixel rate is the maximum number of pixels the graphics card could possibly write to the local memory per second - measured in millions of pixels per second. The number 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 outputting the pixels (image) to the screen. The actual pixel rate also depends on quite a few other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the potential to reach the max fill rate.