My Technology Blog

I recently have upgraded my desktop computer;

on my shopping list was

1. Gigabyte ATI 3870 512M PCIe HDMI Video Card
2. Gigabyte ATI 3870 512M PCIe HDMI Video Card
3. Tagan 800 Watt Power Supply
4. Asus P5KC
5. Intel Quad Core Q6600

Looking at the specs of everything, I was assuming that I would be able to run crossfire and my Terratec 2400i on the P5KC which is based on the P35 Chipset from Intel.

The specs on Asus's webpage state that it has 2x PCIE x16 slots that support crossfire, and 1xPCIE x1 slot and a few PCI slots.

I thought awesome I need all the PCIE slots for crossfire and my TV tuner.

I installed everything last Tuesday, the install went well and everything was looking good.

Then I did some poking around and found that I would need to enable crossfire in ATI's Catalyst Control Center however there was no option to enable crossfire when I opened the control center.

I downloaded a copy of GPU-Z and to my surprise the two graphics cards were listed. However the second one was running at x1 instead of x16. The gpu load on the second graphics card was %99 and the temperature was through the roof at 75-80 degrees. The 3870 is a card that runs at a high temperature however 70-80 when it wasn’t even meant to be doing anything meant there was something wrong.

I quickly shutdown the computer and removed the card. Booted back up with just one graphics card and everything was fine.

I then though maybe I had purchased a motherboard that didn’t support crossfire, I started reading the user manual. I quickly found out that it did indeed support crossfire. However to run the second x16 slot at x4 for crossfire it disabled the PCIE x1 slot. Well that’s what the manual said.

Lets face it who reads a motherboard manual before they purchase the motherboard?

It wasn’t disabling the slot however it was forcing it to run at x1 because I had a card in a x1 slot.

I removed my TV tuner card and like magic the option for crossfire appeared in the control center. And GPU-Z was reporting that I was running crossfire, awesome I though, I can have crossfire and no TV tuner or a TV tuner and no crossfire.

I called the computer shop and explained in depth how the product was not as described and that I would like to return it. They agreed that I was able to return it as long as it was in a resalable condition.

I still didn’t know if there was a motherboard that could actually support crossfire and PCIEx1 slots.

I was also able to find a Foxconn board that has trifire (3 ATI graphics cards), the review for the board stated that the PCIEx1 slots were disabled when the third graphics card was inserted. This board was based on the x38 chipset.

I started looking at the x38 chipset and managed to find the detailed block diagrams form gig abite’s webpage for both the P35 and x38 chipset. The diagrams made it clear that I would need to get a x38 motherboard to use crossfire and a PCIEx1 card.

I returned the Asus P5KC and exchanged it for a giga-byte GA-EX38-DS4, I installed it today and I’m one happy camper. J

So in conclusion Asus should state this in there specifications on their webpage to avoid a lot of confusion, giga – byte do this and well it proves that you can do it, and you can never do enough research before you purchase something. ><