problem with dsp in cisco as5300

i observe in my as5300 this result
ALG01#show call resource voice stats

Resource Monitor – Dial-up Resource Statistics Information:

DSP Statistics:

Utilization: 44 percent
Total channels: 90
Inuse channels: 63 *****
Disabled channels: 0
Pending channels: 0
Free channels: 27

DS0 Statistics:

Utilization: 43 percent
Total channels: 124
Addressable channels: 60
Inuse channels: 26 ****
Disabled channels: 0
Free channels: 34

th ediferance between dep in use and ds0 in use is very large but when the number of the dsp in use equal 90 we d’ont put a call unless we reboot the as5300 can somme body explain me for way this diference andhow i resolve this problem