Latency time On serial Converter and PCI Board

Good evening.
I know that there is some problem with latency time in Usb To Serial Converter (tipical it's about 16ms).

I want to ask you if this problem is avoided with dedicated bord in PCI Slot istalled on PC.
And I desired to have a confirm about the tipical value of this kind of board (about 1ms).

I have found a PCI Board (n° model: CD-IOD-0502) with two serial but I can't found the specification about the latency time. In this case I must consider the tipical latency time value of PCI (about 1 ms)?

Thank's a lot!