Design question : Normalize or Not to normalize ?

Hi gurus,

In our custom HR application, the employee master table has about 3,8 million rows. Many transactions table has FK referring to the Big master table.
(attached is the script sample)
Question :
Since the master table is big enough, should I still normalize here ? Means I have to JOIN to employee table to get the ENAME with the risk of slow join to big reference table ??
Or this is the case where we should sacrifice normalization for performance?

Thank you for your help,
xtanto         

CREATE TABLE EMP
( EMPNO NUMBER(4) NOT NULL PRIMARY KEY,
  ENAME VARCHAR2(30),
  bla..bla.. another 50 columns );

CREATE TABLE PROMOTION
( PROMOTION_ID NUMBER(6) NOT NULL PRIMARY KEY,

  EMPNO        NUMBER(4) NOT NULL ,
  ENAME        VARCHAR2(30),   bla..bla..bla );