Washington, D.C. 20549

                                 SCHEDULE 13G/A

                    Under the Securities Exchange Act of 1934
                               (Amendment No. 3)*

                                Vicor Corporation
                                (Name of Issuer)

                          Common Stock, $0.01 par value
                         (Title of Class of Securities)

                                 (CUSIP Number)

                                December 31, 2007
                      (Date of Event which Requires Filing
                               of this Statement)

Check the  appropriate box to designate the rule pursuant to which this Schedule
is filed:

                                [X] Rule 13d-1(b)
                                [ ] Rule 13d-1(c)
                                [ ] Rule 13d-1(d)

*The  remainder of this cover page shall be filled out for a reporting  person's
initial filing on this form with respect to the subject class of securities, and
for any  subsequent  amendment  containing  information  which  would  alter the
disclosures provided in a prior cover page.

The information required on the remainder of this cover page shall not be deemed
to be "filed" for the purpose of Section 18 of the  Securities  Exchange  Act of
1934 ("Act") or otherwise  subject to the liabilities of that section of the Act
but  shall be  subject  to all other  provisions  of the Act  (however,  see the

                          Continued on following pages
                                Page 1 of 5 Pages

                                                               Page 2 of 5 Pages

1        Names of Reporting Persons
         I.R.S. Identification Nos. of above persons (entities only)


2        Check the Appropriate Box If a Member of a Group (See Instructions)
                                        a.   [  ]
                                        b.   [  ]

3        SEC Use Only

4        Citizenship or Place of Organization


                            5             Sole Voting Power
Number of                                          2,732,200
Beneficially                6             Shared Voting Power
  Owned By                                         0
Reporting                   7             Sole Dispositive Power
    Person                                         2,732,200
                            8             Shared Dispositive Power

9        Aggregate Amount Beneficially Owned by Each Reporting Person


10       Check Box If the Aggregate Amount in Row (9) Excludes Certain
         Shares (See Instructions)

                                    [   ]

11       Percent of Class Represented By Amount in Row (9)


12       Type of Reporting Person (See Instructions)

                                    IA, CO

                                                               Page 3 of 5 Pages

Item     1(a)     Name of Issuer: Vicor Corporation (the "Issuer").

         1(b)     Address of the Issuer's Principal Executive Offices: 25
                  Frontage Road, Andover, MA 01810

Item     2(a) - (c)        Name, Principal Business Address, and Citizenship of
                           Person Filing:
                           Pequot Capital Management, Inc.
                           500 Nyala Farm Road, Westport, CT, 06880
                           which is a Connecticut corporation.

         2(d) Title of Class of Securities: Common Stock, $0.01 par value

         2(e) CUSIP Number: 925815102

Item     3.       This statement is filed pursuant to Rule 13d-1(b)(1)(ii)(E).
                  Pequot  Capital  Management,  Inc.  is an  investment  adviser
                  registered under Section 203 of the Investment Advisers Act of

Item     4.       Ownership:

                  Ownership  as of December 31, 2007 is  incorporated  herein by
                  reference  from  items (5) - (9) and (11) of the cover page of
                  the Reporting Person.

Item     5.       Ownership of Five Percent or Less of a Class:

                  Not applicable.

Item     6.       Ownership of More than Five Percent on Behalf of Another

                  The Reporting Person is an investment adviser registered under
                  Section  203 of the  Investment  Advisers  Act of 1940 and, as
                  such,  has  beneficial  ownership  of the shares which are the
                  subject of this filing through the  investment  discretion the
                  Reporting Person exercises over its clients' accounts.

Item     7.       Identification and Classification of the Subsidiary Which
                  Acquired the Security Being Reported on by the Parent
                  Holding Company:

                  Not applicable.

Item     8.       Identification and Classification of Members of the Group:

                  Not applicable.

Item     9.       Notice of Dissolution of Group:

                  Not applicable.

                                                               Page 4 of 5 Pages

Item     10.      Certification:

                  By signing  below I certify  that, to the best of my knowledge
and belief,  the securities  referred to above were acquired and are held in the
ordinary  course  of  business  and were not  acquired  and are not held for the
purpose of or with the effect of  changing  or  influencing  the  control of the
Issuer of such  securities  and were not acquired and are not held in connection
with or as a participant in any transaction having such purpose or effect.

                                                               Page 5 of 5 Pages


      After reasonable  inquiry and to the best of my knowledge and belief,  the
undersigned  certifies that the information set forth in this statement is true,
complete and correct.

Date:  February 14, 2008           PEQUOT CAPITAL MANAGEMENT, INC.

                                   By:      /s/ Aryeh Davis
                                   Name:    Aryeh Davis
                                   Title:   Chief Operating Officer,
                                            General Counsel and Secretary