shared buffers and startup process

Hi,
I have a master slave setup with streaming replication.
I have a lots of wal files that were moved from master but not applied yet
, a big delay in the replica.
The replica is not working on hotstandby mode , no conflicts to delay
wals apply on it.

I would like to know if increasing the amount of shared-buffers could help
the startup process applying the wals. I would like to know if in
the process of reading the wals and applying them, blocks that should be
written will be brought to shared buffer or not?? If yes, having a bigger
shared buffer will keep as much as possible the amount of pages there and
increase the startup process's speed avoiding pages's replacement and going
to the OS cache and maybe to the disk .
Does it make sense?

Thanks in advanced.

Regards,
Joao