what is your dosbox version and where have you got it from?
what is your Operating System?
what are your PC specifications?
what games have problems?
post content of "DOSBox Status Window"
enclose your dosbox's config file

Dosbox version : 0.73 (I've download from the official website)
OS : Window Seven 32bits, but the same problem occurs on XP SP 2
PC specs : Intel Core 2 duo 2.38GHz, 3Go of RAM, nVidia GeForce 8400M GS
I've this problems on all the games I play : Archemidean Dynasty, Albion, The Settlers 2, Tyrian 2000, Jazz Jackrabbit, Syndicate wars, etc.

Content of DOSBox Status Window :

DOSBox version 0.73 Copyright 2002-2009 DOSBox Team, published under GNU GPL. --- CONFIG:Loading primary settings from config fi […]
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DOSBox version 0.73
Copyright 2002-2009 DOSBox Team, published under GNU GPL.
---
CONFIG:Loading primary settings from config file C:\Users\Nator\AppData\Local\DO
SBox\dosbox-0.73.conf
MIDI:Opened device:win32
DOS keyboard layout loaded with main language code FR for layout fr

try different output=
every rate= to 44100
blocksize=1024
fized cycles

Thanks for your help, it work perfectly fine now.

try it one by one and tell us what helped

All rate=44100
Blocksize=1024

No need for the fixed cycles.

both ? or just one of them or any of them?
have you changed output?

I haven't change the output. And for the rate, I've changed these ones :

[mixer]
rate
[sblaster]
oplrate
[gus]
gusrate
[speaker]
pcrate
tandyrate

With the blocksize changed to 1024.

would it be enough to change only blocksize without changing rates
or
would it be enough to change only rates without changing blocksize?

No, I needed to change both. Maybe it's just my PC.

thanks for testing it out.
44100 with 1024 is currently my favorite setup as well

I remember when I was testing scrolling the title menu of "Vinyl Goddess from Mars" it also needed:
rate=44100
Blocksize=1024
to remove the delay.