ECS 865PE-A problems

I have ECS 865PE-A motherboard and one problem about it. In the BIOS chapter in user's manual you can choose 266/333/400/Auto settings for DDR modules.
In the BIOS on my motherboard 400MHz option is missing. Ok. Maybe I could live with 333MHz, but whatever the choice is, 266/333/Auto, the memory frequency stays at 266 (133MHz). I've tried different DDR400 memory modules from different manufacturers, both in single and dual channel, and nothing helps. The BIOS version is 2.3a, and it is the newest version. My processor is Celeron D @ 2,93GHz (22x133).
It would be stupid to link the FSB and the memory speed together. Or not?
What should I do?

 

look on the mobo and see if there is FSB jumper settings...

 

No...