Filesystems, Disks and Memory

I have a lot of processes all of which need to write quite
a lot of data to the filesystem ( to a single file).
This is managed today in the following way : all the processes
write the data to a shared memory block, which is manged by a process that empties it to a file, thus allowing more space for
writing by the other processes.
It is now argued that this is slow and time- consuming,
specifically in times of high load on the shmem resource
(since each read/write is performed via a lock management
facility).
My question is : Will it be faster to dump the whole idea
of the shared memory and use the buffers that the O.S
provudes ? What type of locking will then be necessary ?

I am working on a AIX , RS6000 machine.

Thank you in advance for your comments !

Please do not cross post questions. This will only fragment the discussion. The duplicate thread is here. I will close this thread.