Alright I got it. Hope it helps!
[dosbox]
memsize=16
#vmemsize=2
#vmemsizekb=0
machine=svga_s3
[render]
aspect=false
frameskip=0
[cpu]
core=dynamic
cputype=auto
cycles=max 105%
cycleup=500
cycledown=500
[speaker]
pcspeaker=true
pcrate=8000
tandy=off
tandyrate=22050
disney=false
[midi]
mpu401=none
[gus]
gus=false
[sblaster]
sbtype=sb2
mixer=true
oplmode=auto
oplemu=fast
oplrate=16000
[mixer]
nosound=false
prebuffer=15
rate=16000
blocksize=512
[ipx]
ipx=false
[serial]
serial1=disabled
serial2=disabled
serial3=disabled
serial4=disabled
[dos]
xms=true
ems=true
umb=true
[joystick]
joysticktype=none
[autoexec]
mount c: “<games>/Might and Magic 3 – Isles of Terra (1991)/MM3/”
c:
MM3.EXE