The ivr voice qulity is very bad when active calls goes higher

hello there,
I have a asterisk 11.17 run in a server has a cpu E5-2640 v3 @ 2.6GHz 32 core, 64G memory.and the active calls is 250. system load is 17 or higher,cpu usage upto 400% sometimes.
Now i have a problem when in a rush hour , somebody call in and the system playback a ivr voice, sometimes the voice have a very bad qulity. the ivr voice code is wav .when we change it to gsm code,the voice change better qulity,but not so good as it play in web brower.

In night ,there is nobody make calls, the ivr voice is good. someone can tell me how to change the situation? Or is there any other information i can tell ,just tell me…thx so much.

What codec are you using for the incoming lines? If it anything but GSM, you have a disk throughput problem, and/or insufficient memory. (GSM is smaller on disk that some other formats, so requires less disk space and less cache space.)

Generally there are too many unspecified variables here to know which resource limit you have exceeded.

The incoming lines using g711 (alaw) ,and out going calls also use g711 .

is there any other idea?

As I said, it appears to be correlated with the amount of file system activity, so I think you are overloading the disk and don’t have enough cache memory. Are you using a VM, as that would be the most likely reason for being resource starved.

thanks for reply.
the system run in a phisical HP server,not a VM.
and as i memsioned the ivr wav files can play in webpages very well.

I don’t see how their playing in web pages relates to the ability of Asterisk to read them in a timely fashion.

sorry, so late to reply…
here is the server’s top command shows.