Visiontek 4850/Motherboard problem

[midlorollin]

Hi, i just built a new rig. I put in two Visiontek 4850s, on a Gigabyte MA790X board. The specs for the board state that the two slots are indeed both x16, however when i look in my catalyst settings it claims they are only at x8. Anything i run (gaming-wise) runs laggy, and falls apart of crashes after a short while. I flashed the BIOS and there doesn't seem to be any other things i can think of to remedy the situation.

I run:
AMD 9850 2.5Ghz
Gigabyte GA MA790X-DS4
8.0GB Corsair DDR2
CrossfireX Visiontek 4850s
Running Vista-64bit, and FedoraCore 9

And this is the output i get in Catalyst Control

Primary Adapter
Graphics Card Manufacturer Built by ATI
Graphics Chipset ATI Radeon HD 4800 Series
Device ID 9442
Vendor 1002

Subsystem ID 0502
Subsystem Vendor ID 1002

Graphics Bus Capability PCI Express 2.0
Maximum Bus Setting PCI Express 2.0 x8

BIOS Version 011.003.000.000
BIOS Part Number 113-B50102-103
BIOS Date 2008/05/23

Memory Size 512 MB
Memory Type GDDR3

Core Clock in MHz 625 MHz
Memory Clock in MHz 993 MHz
Total Memory Bandwidth in GByte/s 59 GByte/s


Linked Adapter
Graphics Card Manufacturer Built by ATI
Graphics Chipset ATI Radeon HD 4800 Series
Device ID 9442
Vendor 1002

Subsystem ID 0502
Subsystem Vendor ID 1002

Graphics Bus Capability PCI Express 2.0
Maximum Bus Setting PCI Express 2.0 x8

BIOS Version 011.003.000.000
BIOS Part Number 113-B50102-103
BIOS Date 2008/05/23

Memory Size 512 MB
Memory Type GDDR3

Core Clock in MHz 625 MHz
Memory Clock in MHz 993 MHz
Total Memory Bandwidth in GByte/s 59 GByte/s


Thanks for any help.

 

[CCT]

The old adage 'RTFM' applies:

"(The PCIE_16_1 slot supports x16; the PCIE_16_2 supports x8.
The PCI Express x16 slots conform to PCI Express 2.0 standard.)", and

"(Note 3) When the CrossFireXTM technology is enabled, the PCIE_16_1 slot will operate in x8 mode. If you are installing a single PCI Express x16 graphics card, please install it in the PCIE_16_1 slot for optimum performance."


Using 2 cards they have to default to the lower x8 setting.

 

[midlorollin]

why would one be x8 though? the motherboard specifications state that both pci-e slots are x16.

 

[CCT]

That would be a question to ask the Gigabyte people, not me.