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Radeon HD 4870 X2 And HD 4870 CrossFire (CF) Compared

Radeon HD 4870 X2: Four Cards Compared
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This comparison focuses on driver optimizations. We have seen in the past that dual-chip cards performed behind a pair of single-GPU boards in tandem, even though both graphics chips sit on the same board and communicate directly with each other. One factor was the different clock speed. Because single-chip cards had better cooling, they also used to have more power when two of them were combined in CrossFire (CF) mode. The Radeon HD 4870 X2 has no disadvantages here. The clock speed of the graphics processor and memory are the same as on the single-chip card.

The results are slightly beyond the measurement tolerances, but you can’t see a clear advantage from the combination.

Assassins Creed in fps 1280
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HD 4870 X2 8.10 QX@3.67 65.4 66.9 67.5 51.3 52.2 52.8 356.1
HD 4870 CF 8.10 QX@3.67 68.3 66.8 64.8 51.3 51.1 51.0 353.3
Performance difference in percent -4.2 0.1 4.2 0.0 2.2 3.5 0.8

Call of Duty 4 shows a slight performance decrease; the dual-chip card performs worse.

Call of Duty 4 in fps 1280
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HD 4870 X2 8.10 QX@3.67 276.2 265.4 226.5 239.3 199.9 177.1 1384.4
HD 4870 CF 8.10 QX@3.67 275.2 254.5 238.8 248.4 212.4 186.5 1415.8
Performance difference in percent 0.4 4.3 -5.2 -3.7 -5.9 -5.0 -2.2

In Crysis, the larger graphics memory makes the difference: the 2 x 1 GB of the HD 4870 X2 wins when anti-aliasing is turned on.

Crysis High in fps 1280
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HD 4870 X2 8.10 QX@3.67 34.2 31.1 31.2 31.8 29.1 29.1 186.5
HD 4870 CF 8.10 QX@3.67 34.2 31.6 31.0 31.9 27.4 26.4 182.5
Performance difference in percent 0.0 -1.6 0.6 -0.3 6.2 10.2 2.2

At the highest quality setting, you can also see a clear trend in favor of the X2 card. The larger graphics memory makes even more of a difference here.

Crysis Very High in fps 1280
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HD 4870 X2 8.10 QX@3.67 29.4 26.3 25.7 27.4 24.4 23.8 157.0
HD 4870 CF 8.10 QX@3.67 29.2 26.4 25.8 26.5 23.1 18.8 149.8
Performance difference in percent 0.7 -0.4 -0.4 3.4 5.6 26.6 4.8

Although the differences lie within the tolerance of the measurement, we’re tempted to say that the 2% to 3% increase in performance results from the lower CPU load of the dual-chip card, because CrossFire has to manage two single-GPU boards.

ET: Quake Wars in fps 1280
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HD 4870 X2 8.10 QX@3.67 90.1 87.6 89.1 86.4 86.3 86.1 525.6
HD 4870 CF 8.10 QX@3.67 87.1 85.7 86.6 84.3 84.3 84.6 512.6
Performance difference in percent 3.4 2.2 2.9 2.5 2.4 1.8 2.5

Here again, you can see a slight difference. The X2 performs slightly better, but almost all results are within the measurement tolerance.

Half Life 2 Episode 2 in fps 1280
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HD 4870 X2 8.10 QX@3.67 130.3 123.5 119.9 128.6 123.4 122.4 748.1
HD 4870 CF 8.10 QX@3.67 130.2 119.3 120.0 125.4 120.5 118.6 734.0
Performance difference in percent 0.1 3.5 -0.1 2.6 2.4 3.2 1.9

Mass Effect shows exactly the opposite of what we said about the lower CPU load. The defeat is significant and really hurts, because there are many DirectX 10 games that are based on the UT3 engine.

Mass Effect in fps 1280
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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 CF 8.10 QX@3.67 132.3 129.7 128.8 124.8 95.9 76.9 123.2 93.7 75.1 980.4
Performance difference in percent -0.8 0.0 -3.0 -6.9 -8.7 -8.2 -7.4 -8.5 -8.1 -5.2

Flight Simulator is very CPU-sensitive. The results are within the measurement tolerance.

MS FlightX SP2 in fps 1280
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HD 4870 X2 8.10 QX@3.67 29.1 29.7 29.4 29.8 29.8 29.3 177.1
HD 4870 CF 8.10 QX@3.67 29.9 29.8 29.7 30.1 30.5 30.2 180.2
Performance difference in percent -2.7 -0.3 -1.0 -1.0 -2.3 -3.0 -1.7

Very balanced; we can’t see any advantage in a combination.

World in Conflict in fps 1280
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HD 4870 X2 8.10 QX@3.67 53.5 56.1 54.5 50.0 52.9 52.5 319.5
HD 4870 CF 8.10 QX@3.67 53.2 55.4 53.3 51.1 52.8 51.3 317.1
Performance difference in percent 0.6 1.3 2.3 -2.2 0.2 2.3 0.8

The Radeon HD 4870 X2 can compete with the HD 4870 in CrossFire—there are no more significant performance drops as we have seen them with older dual-chip cards like the Radeon HD 3870 X2.

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