Poor queries performance / check storage clause of the table ?

Hi ,

 I always have a disastrous execution time each time a DML relates to same table PRODUCTS !.

How can I check that does not come from storage clause of the table PRODUCTS itself ?

Which are the important points to check in a storage clause of a table or index ?

What others points to check related to storage ?

Thank you for help .

GD.

create table PRODUCTS
(
  NO_PARTITION      NUMBER(10) not null,
  -- Others columns ...
)
partition by range (NO_PARTITION)
(
  partition P_PART_1 values less than (1)
    tablespace TBS_DATA
    pctfree 25
    pctused 40
    initrans 1
    maxtrans 255
    storage
    (
      initial 40K
      next 1M
      minextents 1
      maxextents unlimited
      pctincrease 0