i have a funny problem when i play the need for speed se on my notebook.

my nfs version won't start without a inserted & mounted cd
(probably because i checked "full install" during setup, with movies and music...)

now the game would run fine for a couple of laps/minutes,
then it would suddenly freeze for about 2 seconds, during which the cd drive would audibly spin up.
This usually happens when an audio clip, eg. "one lap to go!", is being played,
but has also occured at other times

being the lazy person that i am, i decided to create a cd-image and mount it with dosbox,
so i could play the game wherever i am.
also i hoped that this would fix the freezing issue - only it didn't

it still freezes, now for only 1 second, during which, instead of the cd spinning, the hdd-led would light up
(presumabely because the image is being accessed)
additionally it now freezes more often, making the game ALMOST unplayable-
i've often crashed my car because the game freezed right before a tight corner

i'm quite sure that the cd/image is the cause, rather than my notebook not being able to run nfs

i'm using the current dosbox-version (0.74)

the only conf-options that i've changed are:

graphicscard: vesa_nolfb (more fluid than s3)
output: ddraw
fullscreen: true
fullscreen resolution: 1024x768
no scaling
cpu cycles: max
and some autoexec lines to mount the cd/image and to start the game...

my hardware:

hp dv6-6007sg notebook
core i3-2310m
4gb ram
hd graphics 3000 & hd 6770m
win7 pro 64bit