The second CrossFire generation, called Native CrossFire, solved the two main problems found on previous generation: the requirement of a “master”card (as the composition engine is now embedded on the graphics chip of all video cards that support Native CrossFire and CrossFireX) and the cable issue, using a bridge just like SLI for high-end cards. Actually two bridges are needed to connect the cards, as each card has two connectors.
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Figure 9: Native CrossFire connectors on a Radeon video card.
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Figure 10: Native CrossFire bridge. You need two of them.
For mainstream cards ATI also decided to use the same approach used by nVidia: the cards are connected thru the PCI Express bus, not requiring an external bridge.
Native CrossFire increased the maximum resolution to 2560x2048.
On the table below you have a list of all possible combinations of video cards using Native CrossFire and a column indicating if the bridges are necessary or not. So you cannot hook up your Radeon HD 2900 Pro to a Radeon HD 2600 XT, for example.
| First Video Card | Second Video Card | Bridges Required |
Radeon HD 3870 X2
Radeon HD 3870
Radeon HD 3850 | Radeon HD 3870 X2
Radeon HD 3870
Radeon HD 3850 | Yes |
| Radeon HD 3650 | Radeon HD 3650 | Yes |
Radeon HD 3470
Radeon HD 3450 | Radeon HD 3470
Radeon HD 3450 | Yes |
Radeon HD 2900 XT
Radeon HD 2900 Pro | Radeon HD 2900 XT
Radeon HD 2900 Pro | Yes |
Radeon HD 2600 XT
Radeon HD 2600 Pro | Radeon HD 2600 XT
Radeon HD 2600 Pro | Yes |
Radeon HD 2400 XT
Radeon HD 2400 Pro | Radeon HD 2400 XT
Radeon HD 2400 Pro | Yes |
| Radeon X1950 Pro | Radeon X1950 Pro | Yes |
| Radeon X1950 GT | Radeon X1950 GT | Yes |
| Radeon X1650 XT | Radeon X1650 XT | Yes |
Radeon X1650 Pro
Radeon X1650
Radeon X1600 XT
Radeon X1600 Pro | Radeon X1650 Pro
Radeon X1650
Radeon X1600 XT
Radeon X1600 Pro | No |
| Radeon X1550 | Radeon X1550 | No |
| Radeon X1300 XT | Radeon X1300 XT | No |
Radeon X1300 Pro
Radeon X1300 | Radeon X1300 Pro
Radeon X1300 | No |
And finally the third generation, CrossFireX, is a Native CrossFire connection that allows you to connect up to four video cards based on ATI/AMD chips. The connectors and bridge are identical to Native CrossFire, the difference is how they are connected (see Figure 11). So far only Radeon HD 3870 and Radeon HD 3850 support this new mode. CrossFireX is part of AMD Spider gaming platform. Of course you will need a motherboard with three or four PCI Express x16 slots in order to use more than two video cards. It is very imoportant to notice that AMD started recently calling all generations of CrossFire technology as "CrossFireX".
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Figure 11: CrossFireX.
