new Pc + Vista --> frequency variations in stepper

[step-walk]

Hi,
I have a problem with my cnc machine. After two Ide Hdd had broken under my old Fujitsu Scenic Pc I decided to exchange the old Fujitsu mainboard with a new Elitegroup mainboard with dual core cpu. As i wasn't able to install xp on this mainboard I had to install windows Vista. I have already read the Vista Readme from the Mach3 Homepage and installed everything as described. Nevertheless the machine isn't running fine, as there a short, continuous variation in the frequency in the stepper (you can hear this). Under xp in combination with the old Fujitsu mainbaord everything went fine.
Now I'm not sure if the mainboard or Vista is responsible for this mistake.
Do you have any advice?

With best regards from Germany and thx for your help in advance
Step-walk 

[Jeff_Birt]

Have you gone through all the Mach optimizations for XP (as they apply to Vista)? Have you tried a driver test? What did it show?

I've seen some motherboards that just won't run the LPT driver correctly though.

[ger21]

If you have them, disable EIST and C1E in the bios.

[step-walk]

Hi,
ger21 you have made my day! Machine is running now very very smooth and clean. All i did is was to disable C1E in Bios. I though i have to give up the mainboard and was already on the verge of selling this mainboard and exchanging it with a new one.
Its unvelievable how clean the machine now runs, much better than with the old Fujitsu one. Its runs so well that you might think servos are assembled (and not steppers) Obviously the old mainboard was to slow for high frequencies. 

Thx, thx, and again thx all for you help
Step-walk