Asus Crosshair IV Extreme
Lucid Hydra 200 Series
Before I get started, I wanted to summarise Lucid Hydra in a few words.
At present, ATi and nVidia incorporate a similar means of implementing Multi GPU technology - Alternate Frame Rendering (AFR). As the name suggests, each graphics card is responsible for the rendering of each frame in a game. It may sound crude and in fairness it does sound a little primitive. Obviously the implementation works well but it isn't flawless either.
Lucid's implementation is a lot more complex. The Hydra processing unit is designed to link with either the northbridge or processor. While the approach requires a dedicated Lucid chip, it also requires a very clever driver. Normally, the graphics card's driver would handle Direct X and OpenGL commands, but instead Mr Lucid acts as a middle man. The software carefully considers the power required for each command, then appropriately balances the load between each graphics card. It should be mentioned that Lucid splits the same frame and recompiles it.
On paper it sounds like a solid concept and our previous experience with it reveals respectable performance gains.
So what's in it for you?
In the past, we have already worked on motherboards featuring Lucid Hydra technology. However, most implementations that we have seen are used to make the northbridge’s PCI-Express functionality redundant. Usually, this is because previous Lucid boards have utilised relatively entry level chipsets which lack in the PCI-E lane department anyway. This is where the Crosshair IV Extreme stands out.
So what exactly does Lucid Hydra bring to the table?
With the exception of “hacked” SLI drivers, the only way to go about a SLI setup on Socket AM3 was to buy into relatively unpopular nVidia 980a MCP core logic. Quite predictably, if you decide to follow that route you can forget about using ATi’s CrossfireX technology. You simply cannot win… until now.
Lucid’s Multi GPU implementation is entirely independent of the core logic and graphics cards that it must interface with. This means the technology can be deployed on most chipsets but can also leverage the power of multiple ATi, nVidia and Mixed GPU configurations.
What I have said thus far applies to all Lucid equipped motherboards. However, Asus’ design offers a greater level of flexibility.
As shown above, the Crosshair IV Extreme allows the end user to harness the 890FX’s native 16x/16x lane CrossfireX, any of Lucid’s Dual/Triple/Quad configurations…or both. As Lucid Hydra is (by comparison to SLI/Crossfire) in its infancy, it could well be the case that a particular ATi Multi GPU arrangement might perform better with Crossfire’s proven “Alternate Frame Rendering” technique. At any rate, the ability to use either technology is very useful indeed.
Also note that even with Lucid operation, the CH4E always draws one 16x lane to the primary graphics card. Meanwhile Lucid pulls another 16x lane to handle the rest of the graphics cards in the configuration. In effect, the Crosshair IV Extreme has more PCI-Express lanes to play with, compared to previously reviewed samples such as the MSI 870A FUZION Power Edition.
Note that 4 way Lucid "A" and "N" modes will be available with a driver shortly.
Upon face value, it seems clear that the Crosshair IV Extreme has an incredibly flexible Multi GPU arrangement, which should suit every enthusiast’s needs.