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Radeon HD 4870 And HD 4870 X2 Compared

Radeon HD 4870 X2: Four Cards Compared
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In the following direct comparisons, we will provide a more detailed analysis of the advantages of the X2 for different games and resolutions. In this analysis, we compare the frame rates (fps) and give them as a percentage that shows the gain or drop in performance in each case. The first comparison addresses the old question: is a single-chip card enough, do you need CrossFire, and how much do you gain from a second graphics chip?

Assassin’s Creed runs absolutely perfectly with the Radeon HD 4870. A slight increase can only be seen above 1920x1200 pixels with anti-aliasing. But you don’t really need a dual-chip card when the boost is only 12.6%.

Assassin’s Creed in fps 1280
0xAA
1680
0xAA
1920
0xAA
1280
4xAA
1680
4xAA
1920
4xAA
Overall
HD 4870 X2 8.10 QX@3.67 65.4 66.9 67.5 51.3 52.2 52.8 356.1
HD 4870 8.10 QX@3.67 69.0 68.3 65.6 51.8 51.0 46.9 352.6
Performance difference in percent -5.2 -2.0 2.9 -1.0 2.4 12.6 1.0

Call of Duty 4 can be played smoothly with a single-chip card. The dual-chip card raises performance to a whole new level, though—the gain of 62% to over 100% is gigantic and there should not be any shakiness left even in missions with heavy graphics demands.

Call of Duty 4 in fps 1280
0xAA
1680
0xAA
1920
0xAA
1280
4xAA
1680
4xAA
1920
4xAA
Overall
HD 4870 X2 8.10 QX@3.67 276.2 265.4 226.5 239.3 199.9 177.1 1384.4
HD 4870 8.10 QX@3.67 170.2 140.0 114.8 125.7 101.0 87.4 739.1
Performance difference in percent 62.3 89.6 97.3 90.4 97.9 102.6 87.3

In Crysis, a dual-chip card pays off in high resolutions with anti-aliasing turned on. After more than a month of optimizing CrossFire, Crysis has finally become faster and benefits from the two HD 4870 X2 GPUs. At lower resolutions, the CPU limits performance, determining the maximum frame rate.

Crysis High in fps 1280
0xAA
1680
0xAA
1920
0xAA
1280
4xAA
1680
4xAA
1920
4xAA
Overall
HD 4870 X2 8.10 QX@3.67 34.2 31.1 31.2 31.8 29.1 29.1 186.5
HD 4870 8.10 QX@3.67 38.2 34.5 31.8 31.5 21.9 18.6 176.5
Performance difference in percent -10.5 -9.9 -1.9 1.0 32.9 56.5 5.7

With the highest picture quality and anti-aliasing, you really need twice the graphics power. The gain at higher resolutions with AA is increased even more through the larger graphics memory of 2 x1 GB, which is the reference spec for AMD’s Radeon HD 4870 X2. If you have a Radeon HD 4870 with 1 GB of graphics memory, the difference in going to the X2 will be smaller. The values shown in the table are limited by the 512 MB test card.

Crysis Very High in fps 1280
0xAA
1680
0xAA
1920
0xAA
1280
4xAA
1680
4xAA
1920
4xAA
Overall
HD 4870 X2 8.10 QX@3.67 29.4 26.3 25.7 27.4 24.4 23.8 157.0
HD 4870 8.10 QX@3.67 31.7 25.8 21.8 21.8 15.6 12.1 128.8
Performance difference in percent -7.3 1.9 17.9 25.7 56.4 96.7 21.9

The id engine employing OpenGL responds well to CPU power. The graphics card has less of an impact, so a single chip is enough for this game.

ET: Quake Wars in fps 1280
0xAA
1680
0xAA
1920
0xAA
1280
4xAA
1680
4xAA
1920
4xAA
Overall
HD 4870 X2 8.10 QX@3.67 90.1 87.6 89.1 86.4 86.3 86.1 525.6
HD 4870 8.10 QX@3.67 90.1 87.2 88.7 87.4 86.3 83.8 523.5
Performance difference in percent 0.0 0.5 0.5 -1.1 0.0 2.7 0.4

The Source engine used to drive Half Life 2 responds more to CPU performance, getting hardly any advantage from the dual-chip Radeon HD 4870 X2.

Half Life 2 Episode 2 in fps 1280
0xAA
1680
0xAA
1920
0xAA
1280
4xAA
1680
4xAA
1920
4xAA
Overall
HD 4870 X2 8.10 QX@3.67 130.3 123.5 119.9 128.6 123.4 122.4 748.1
HD 4870 8.10 QX@3.67 132.7 126.4 124.0 132.7 125.3 115.3 756.4
Performance difference in percent -1.8 -2.3 -3.3 -3.1 -1.5 6.2 -1.1

Mass Effect, with the UT3 engine, scales very nicely with the graphics processors (GPUs) used. The gain can be up to 80%. The game runs smoothly only with the dual-chip card, especially with anti-aliasing.

Mass Effect in fps 1280
0xAA
1680
0xAA
1920
0xAA
1280
4xAA
1680
4xAA
1920
4xAA
1280
8xAA
1680
8xAA
1920
8xAA
Overall
HD 4870 X2 8.10 QX@3.67 131.2 129.7 125.0 116.2 87.6 70.6 114.1 85.7 69.0 929.1
HD 4870 8.10 QX@3.67 133.3 105.4 84.2 64.9 49.1 39.2 63.4 48.0 38.4 625.9
Performance difference in percent -1.6 23.1 48.5 79.0 78.4 80.1 80.0 78.5 79.7 48.4

Flight Simulator is unable to take advantage of two-card configurations and consequently doesn’t demonstrate any gain at all.

MS FlightX SP2 in fps 1280
0xAA
1680
0xAA
1920
0xAA
1280
4xAA
1680
4xAA
1920
4xAA
Overall
HD 4870 X2 8.10 QX@3.67 29.1 29.7 29.4 29.8 29.8 29.3 177.1
HD 4870 8.10 QX@3.67 30.9 30.7 30.7 31.4 30.8 31.3 185.8
Performance difference in percent -5.8 -3.3 -4.2 -5.1 -3.2 -6.4 -4.7

World in Conflict without anti-aliasing responds more to CPU speed. With anti-aliasing turned on, the Radeon HD 4870 X2 gains performance, but only pays off at resolutions above 1680x1050 or 1920x1200. Below that, it’s subjectively a waste.

World in Conflict in fps 1280
0xAA
1680
0xAA
1920
0xAA
1280
4xAA
1680
4xAA
1920
4xAA
Overall
HD 4870 X2 8.10 QX@3.67 53.5 56.1 54.5 50.0 52.9 52.5 319.5
HD 4870 8.10 QX@3.67 55.5 58.0 55.1 47.6 40.4 34.5 291.1
Performance difference in percent -3.6 -3.3 -1.1 5.0 30.9 52.2 9.8

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