committing evey X records will severly affect performance, the more you commit the worse the performance

here's a simple illustration you can try

REM =============================================
REM Set timing on and commit after every insert
REM Note the time it takes to complete
REM =============================================


drop table t1
/
create table t1 (col1 number)
/
set timing on
set serveroutput on
begin
for i in 1..9999 loop
insert into t1 values(i);
commit;
end loop;
end;
/



REM =============================================
REM Set timing on and commit after all rows have
REM been inserted.
REM Note the time it takes to complete
REM =============================================


drop table t1
/
create table t1 (col1 number)
/
set timing on
set serveroutput on
begin
for i in 1..9999 loop
insert into t1 values(i);
end loop;
commit;
end;
/