ultimarc ipac 4 joystick button conflict

[bdesruis]

Hello, newbie here,

Building a 4 player arcade on a very fast PC
Using ultimarc ipac 4
1 joystick and 6 buttons per player
When playing a MAME game like defender
Interference between joystick and buttons
Ex: moving and firing at same time looks like it cause a delay in firing
Any idea why

Many Thanks

Ben

[vertexguy]

Maybe it's a usb lag issue?  If you're connecting to a USB hub make sure its sufficiently powered.  I've seen other posts talk about that before.  If not try a different usb 3 port.