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- Date:
- Monday , September 26, 2005
- Author:
- Brent Justice
- Editor:
- Kyle Bennett
- Google +1
ATI Radeon X850 XT CrossFire Review
ATI fights back against NVIDIA with their dual card solution known as CrossFire. Although CrossFire improves performance, do the limitations that exist in ATI’s current dual card implementation make CrossFire a wise investment?
ATI Xpress 200 CrossFire Motherboard Setup:
Reviewers were sent a kit that included a reference ATI Xpress 200 CrossFire-based motherboard, a Radeon X850 XT slave card, a Radeon X850 XT CrossFire master card a dongle, and drivers. The motherboard we received is an AMD-based Xpress 200 CrossFire edition motherboard. Installation of the video cards and RAM is different on this motherboard from what we are use to with an nForce4 motherboard like the ASUS A8N-SLI Deluxe. With the AMD-based Xpress 200 motherboard, we had to set the RAM modules in two adjacent slots in order to run in Dual Channel mode. On the Intel-based Xpress 200 motherboard, you must have the RAM modules in alternate slots for Dual Channel mode. It is important to note this difference so you will be sure you are running in Dual Channel mode. In addition, as we found out, if all four memory slots are populated you will only have the option to run at DDR 333 speeds instead of DDR 400 speeds.
The next configuration difference you need to be aware of is how the two PCI-Express (PCI-E) slots are laid out. The primary PCI-E slot is actually the one farthest from the CPU, nearest the PCI slots. The PCI-E slot nearest the CPU is actually the secondary PCI-E slot. What this means is that you must plug the slave video card, i.e. your initial Radeon X800 or X850 series video card into the secondary slave PCI-E slot, which is nearest the CPU. The primary CrossFire master card needs to be plugged into the primary PCI-E slot farthest from the CPU. If you have the video cards in the wrong slots, you will not be able to enable CrossFire. We found this out the hard way.
If you are going to be running in a single video card configuration on this motherboard, you must install a terminator card in the primary PCI-E slot farthest from the CPU. By default, this motherboard is set to have 8 PCI-E lanes going to each PCI-E slot. If you are only going to be running one video card, however, you will want to terminate the primary PCI-E slot so that all 16 lanes go to the secondary (slave) PCI-E slot for your single video card.
ATI Radeon X850 XT CrossFire Setup:
Now with the knowledge of how everything is laid out on the motherboard, we can focus on setting up CrossFire. In the screenshots above, you see a regular Radeon X850 XT (top) and a Radeon X850 XT CrossFire master card (bottom). You can see that front and back they look the same and are the same length. You would not be able to distinguish between them except by looking at the faceplate to see the connections available. The CrossFire master card has a white port that is much denser with many more pins than a regular DVI port. This is the where the CrossFire dongle connects.
As we noted above, the video cards must be installed in a specific configuration. If you install the video cards the wrong way, Catalyst Control Center will let you know that you need to switch them in order to have CrossFire enabled. We attempted this and were able to install the driver just fine but we were not able to enable CrossFire. There was message under the CrossFire section of the driver control panel that told us to make sure the video cards are in the correct slot. In the above screenshot, you can see the correct configuration for the cards. It is a good thing that these video cards take air in from the front of the case and exhaust it out of the rear since they are right next to each other. There is not much room for airflow between the cards when they are installed.
The dongle provided with the bundle is the cable that facilitates the communication between the video cards for the sharing of data. You can’t really connect this up wrong because one end of it only fits into one connection on the Master Card. You plug the DVI cable coming off it up to the secondary slave’s video card’s DVI port. This completes the connection between the two video cards themselves. As you can see in the second screenshot, the tension on the cable forces the video cards apart when they aren’t properly mounted to a case.
Once you connect the video cards together, then you can plug in your display to the longer cable coming off of the dongle from the master card connection. This is a DVI connector so you can connect an LCD or use a DVI to VGA connector if you have a VGA connection. We did try to hook up our primary display to the VGA port on the slave video card to see what would happen. In the screenshot above, you can see that Catalyst Control Center is telling us to plug the monitor into the cable, so running a primary display off the slave video card will not work. We also tried plugging the monitor into the other DVI port on the master card but we received no signal on the display. It is also very important to note that if your monitor does not support the Extended Display Identification Data (EDID), or it has an incomplete EDID, it may result in the screen going blank during system POST and boot up.
Therefore, this is the complete setup and this is how things should look if you have done everything right. You will need to plug in both video card’s power cables as well as the Molex connector on the motherboard itself for more power. We suggest having these video cards screwed into a case so that the dongle won’t force them apart.