I have an application that runs correctly and works, except for one thing. The app collects data via a serial port, which is emulated through serial1 = directserial realport:com5 and the use of a serial-to-usb adapter. Whenever the serial port isnt plugged in, the app runs quickly and smoothly, but when I plug in the serial port, the app slows down to a crawl. It's not graphically intensive, but it lags whenever I try to input anything and draws each screen very slowly. There's a delay of about 4-6 seconds between input and the program registering the input. I've tried adjusting the CPU setting as suggested in the manual, but that doesn't seem to change things.

I've tried the program in DosBox 0.74 and DoxBox SVN-Daum, and both have the same slowness issue. Thank you in advance for the help.

The computer I'm using is running Windows 7 x64.
Motherboard: HP 179C
Processor: Intel i5 3320M
RAM: 4GB DDR3
Video: Intel HD Graphics 4000
Sound: Intel Display Audio
Video Mode in Dosbox: frameskip=0
aspect=false
scaler=normal2x
CPU settings in DosBox: core=dynamic
cputype=auto
cycles=auto
cycleup=10
cycledown=20