FIRST AMENDMENT TO CREDIT AGREEMENT AND OTHER LOAN DOCUMENTS

Exhibit 10.5

FIRST AMENDMENT TO CREDIT AGREEMENT AND OTHER LOAN DOCUMENTS

THIS FIRST AMENDMENT TO CREDIT AGREEMENT AND OTHER LOAN DOCUMENTS (this “Amendment”) made as of the 10th day of February, 2009, by and among GRIZZLY VENTURES LLC , a Delaware limited liability company (“ Borrower ”), DUPONT FABROS TECHNOLOGY, L.P. , a Maryland limited partnership (“ Guarantor ”), TARANTULA VENTURES LLC, a Delaware limited liability company (“ Additional Guarantor ”), KEYBANK NATIONAL ASSOCIATION , a national banking association (“ KeyBank ”), THE OTHER LENDERS WHICH ARE SIGNATORIES HERETO (KeyBank and the other lenders which are signatories hereto, collectively, the “ Lenders ”), and KEYBANK NATIONAL ASSOCIATION , a national banking association, as Administrative Agent for the Lenders (the “ Agent ”).

W I T N E S S E T H:

WHEREAS, Borrower, Guarantor, Agent, and the Lenders entered into that certain Credit Agreement dated as of October 24, 2008 (as amended herein and as the same may be further varied, extended, supplemented, consolidated, replaced, increased, renewed, modified or amended from time to time, the “ Credit Agreement ”);

WHEREAS, pursuant to the Credit Agreement, Lenders made a loan to Borrower in the original principal amount of $100,000,000.00, increasable up to $250,000,000.00 in accordance with the terms of the Credit Agreement (the “ Loan ”), which Loan is evidenced by, among other things, the Notes made by Borrower to the order of Lenders and delivered from time to time under the Credit Agreement (together with all amendments, modifications, consolidations, increases, supplements and extensions thereof, collectively, the “ Note ”);

WHEREAS, Borrower desires to increase the “Total Commitment” under the Credit Agreement;

WHEREAS , in order to induce additional lenders to join in funding the increase of the Total Commitment, the Agent, the Lenders, the Borrower, Guarantor and Additional Guarantor desire to enter into this Amendment to reflect the increase of the Total Commitment under the Credit Agreement and the delivery by Additional Guarantor of, among other documents, a Guaranty and a mortgage on the additional collateral to further secure the Loan.

NOW, THEREFORE , for and in consideration of the sum of TEN and NO/100 DOLLARS ($10.00), and other good and valuable consideration, the receipt and sufficiency of which is hereby acknowledged, the parties hereto do hereby covenant and agree as follows:

1. Definitions . All the terms used herein which are not otherwise defined herein shall have the meanings set forth in the Credit Agreement, as amended herein.

2. Modification of the Credit Agreement . Borrower, Guarantor, the Lenders and Agent do hereby modify and amend the Credit Agreement as follows:

(a) By inserting the following definitions in Section 1.1 of the Credit Agreement:

“ Additional Guarantor . Tarantula Ventures LLC, a Delaware limited liability company.

Additional Mortgaged Property . That certain Data Center Facility, CH1 owned by Additional Guarantor located at 2200 S. Busse Road, Elk Grove Village, Illinois.

Additional Property Building . The data center located on the Additional Mortgaged Property known as CH1 to consist when fully completed of approximately 485,000 gross square feet and 211,140 raised square feet with a critical load of 36.4 megawatts (the first phase will consist of approximately 121,223 raised square feet with a critical load of 18.2 megawatts), and all of the buildings, structures and improvements now or hereafter located thereon.

Additional Property Leases . The collective reference to all leases, subleases, licenses and occupancy agreements (whether written or oral) affecting the Additional Mortgaged Property or any part thereof now existing or hereafter executed and all amendments, modifications or supplements thereto.

CH1 Assignment of Leases and Rents . The Assignment of Leases and Rents from Additional Guarantor to KeyBank, as agent under a construction loan facility, dated as of December 20, 2007, recorded in the Official Records of Cook County, Illinois as Document No. 0800360020, as amended pursuant to that certain First Amendment to Construction Mortgage, Assignment of Leases and Rents, Security Agreement and Fixture Filing and Assignment of Leases and Rents dated February 10, 2009 between Additional Guarantor and Agent, and as the same may be further modified and amended from time to time.

CH1 Guaranty . The Guaranty given by Additional Guarantor to and for the benefit of Agent and the Lenders, as the same may be modified, amended or ratified.

CH1 Indemnity Agreement . The Indemnity Agreement Regarding Hazardous Materials made by Additional Guarantor and Guarantor in favor of the Agent and the Lenders, as the same may be modified, amended or ratified.

CH1 Indemnity and Guaranty Agreement . The Indemnity and Guaranty Agreement made by Guarantor in favor of the Agent and the Lenders covering the Additional Mortgaged Property, as the same may be modified, amended or ratified.

CH1 Mortgage . The Construction Mortgage, Assignment of Leases and Rents, Security Agreement and Fixture Filing dated as of December 20, 2007 from Additional Guarantor to KeyBank, as agent under a construction loan facility, recorded in the Official Records of Cook County, Illinois as Document No. 0800360019, as amended pursuant to that certain First Amendment to Construction Mortgage, Assignment of Leases and Rents, Security Agreement and Fixture Filing and Assignment of Leases and Rents dated February     , 2009 between Additional Guarantor and Agent, and as the same may be further modified and amended from time to time.

Contribution Agreement . The Contribution Agreement by and between Borrower, Guarantor and Additional Guarantor delivered in connection with this Agreement, as the same may be modified, amended or ratified from time to time.”

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(b) By deleting the following definitions appearing in Section 1.1 of the Credit Agreement in their entirety and inserting in lieu thereof the following:

“ Assignment of Leases and Rents . Collectively, the Assignment of Leases and Rents from Borrower to the Agent dated as of October 24, 2008, recorded in the Official Records of Loudoun County, Virginia as Document No. 20081027-0063823 between Borrower and Agent, as amended by that certain First Amendment to Deed of Trust and Security Agreement and Assignment of Leases and Rents between Borrower and Agent dated February 10, 2009, and as the same may be further modified or amended from time to time, and the CH1 Assignment of Leases and Rents, pursuant to which there shall be assigned to the Agent for the benefit of the Lenders a security interest in the interest of Borrower or Additional Guarantor, as applicable, as lessor with respect to all Additional Property Leases or Leases, as applicable of all or any part of the Mortgaged Property or the Additional Mortgaged Property, as applicable.

Collateral . All of the property, rights and interests of Borrower and Additional Guarantor which are subject to the security interests, security title, liens and mortgages created by the Security Documents, including, without limitation, the Mortgaged Property or the Additional Mortgaged Property, as applicable.

Condemnation Proceeds . All compensation, awards, damages, judgments and proceeds awarded to Borrower or Additional Guarantor by reason of any Taking, net of all reasonable and customary amounts actually expended to collect the same.

Guaranty . Collectively, the Guaranty dated as of October 24, 2008 given by Guarantor to and for the benefit of Agent and the Lenders and the Guaranty dated as of February     , 2009 given by Additional Guarantor to and for the benefit of Agent and the Lenders, and the CH1 Guaranty, as the same may be modified, amended or ratified, such Guaranty to be in form and substance satisfactory to Agent.

Indemnity Agreement . Collectively, the Indemnity Agreement Regarding Hazardous Materials made by Borrower and Guarantor in favor of the Agent and the Lenders and the Indemnity Agreement Regarding Hazardous Materials made by Additional Guarantor and Guarantor in favor of the Agent and the Lenders and the CH1 Indemnity Agreement, as the same may be modified, amended or ratified, pursuant to which Borrower or Additional Guarantor, as applicable, and Guarantor agree to indemnify the Agent and the Lenders with respect to Hazardous Substances and Environmental Laws.

Indemnity and Guaranty Agreement . The Indemnity and Guaranty Agreement dated of even date herewith made by Guarantor in favor of the Agent and the Lenders covering the Mortgaged Property, as the same may be modified, amended or ratified, and the CH1 Indemnity and Guaranty, such Indemnity and Guaranty Agreement to be in form and substance satisfactory to Agent.

Loan Documents . This Agreement, the Notes, the Guaranty, the Indemnity and Guaranty Agreement, the Contribution Agreement, the Security Documents, and all other documents, instruments or agreements now or hereafter executed or delivered by or on behalf of Borrower, Guarantor, or Additional Guarantor in connection with the Loans.

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Management Agreements . Any agreement, whether written or oral, providing for the management of the Mortgaged Property or the Additional Mortgaged Property, as applicable.

Mortgage . Collectively, the Deed of Trust and Security Agreement dated October 24, 2008 from Borrower to a trustee named therein acting on behalf of the Agent for the benefit of the Lenders recorded in the Official Records of Loudoun County, Virginia as Document No. 20081027-0063822, as amended by that certain First Amendment to Deed of Trust and Security Agreement and Assignment of Leases and Rents between Borrower and Agent, and as the same may be further modified or amended from time to time, and the CH1 Mortgage, pursuant to which Borrower or Additional Guarantor, as applicable, has conveyed or granted a mortgage lien upon or a conveyance in fee simple (or of a leasehold, if applicable) of the Mortgaged Property or the Additional Mortgaged Property, as applicable, as security for the Obligations.

Rent Roll . A report prepared by Borrower or Additional Guarantor, as applicable, showing for the Mortgaged Property or the Additional Mortgaged Property, as applicable, its occupancy, lease expiration dates, lease rent and other information in substantially the form presented to Agent prior to the date hereof or in such other form as may be reasonably acceptable to the Agent.

Subordination, Attornment and Non-Disturbance Agreement . An agreement among the Agent, Borrower or Additional Guarantor and a tenant under a Lease or Additional Property Lease, as applicable, pursuant to which such tenant agrees to subordinate its rights under the Lease or Additional Property Lease to the lien or security title of the Mortgage and agrees to recognize the Agent or its successor in interest as landlord under the Lease or Additional Property Lease in the event of a foreclosure under the Mortgage, and the Agent agrees to not disturb the possession of such tenant, such agreement to be in form and substance reasonably satisfactory to Agent.”

(c) By deleting subsections (c), (f) and (g) from the definition of “Change of Control” in Section 1.1 of the Credit Agreement and inserting in lieu thereof the following:

“(c) Borrower, Guarantor or Additional Guarantor consolidates with, is acquired by, or merges into or with any Person (other than a merger permitted by §8.4); or”

“(f) Guarantor fails to own directly or indirectly, free of any lien, encumbrance or other adverse claim, at least one hundred percent (100%) of the economic, voting and beneficial interest of Borrower or Additional Guarantor (except that REIT may own up to one percent (1%) of Safari Ventures LLC, a Delaware limited liability company, the sole member of the sole member of Additional Guarantor) other than any pledge of interests in Borrower permitted by Agent in connection with the Permitted Mezzanine Debt and any foreclosure on such pledge permitted under the Intercreditor Agreement; or”

“(g) Managing Member shall cease to be the sole member of Borrower or Tarantula Interests LLC, a Delaware limited liability company, shall cease to be the sole member of Additional Guarantor, and Managing Member or Tarantula Interests LLC shall fail to own at least one hundred percent (100%) of the membership interest in Borrower or Additional Guarantor, as applicable, free of any lien, encumbrance or other adverse claim other than in connection with a foreclosure contemplated by the Intercreditor Agreement; or”

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(d) In the following sections of the Credit Agreement, the term “Mortgaged Property” shall include the “Additional Mortgaged Property” mutatis mutandis in any place it appears in such section: the definition of “Taking” in Section 1.1, Sections 3.2, 6.6, 6.16, 6.20, 6.23, 7.4(e)(i) and (iii), 7.5(b) and (c), 7.6(b), 7.7, 7.8, 7.12, 7.15, 7.19, 8.2(iv), 8.3(h), 8.6, 8.7, 8.11, 8.16, 14.10, 14.12, 15 and 16.

(e) In the following sections of the Credit Agreement, the term “Borrower” shall also include “Additional Guarantor” mutatis mutandis in any place it appears in such section: Section 3.2, the introductory paragraph of Section 6.20, Sections 6.20(a), (c), (d), (e) and (f), 6.23, 6.25, 7.5(b) and (c), 7.6(b), 7.7, 7.8, 7.12, 7.15, 8.1, 8.2, 8.3, 8.6, 8.7, 8.11, 8.16, 14.11 and 14.12

(f) In the following sections of the Credit Agreement, the term “Building” shall include the “Additional Property Building” mutatis mutandis in any place it appears in such section: Sections 6.23 and 7.7.

(g) In the following sections of the Credit Agreement, the term “Lease” or “Leases” shall include the “Additional Property Leases” mutatis mutandis in any place it appears in such section: Sections 7.4(e), 7.7(g), 7.9, 8.11 and 14.12.

(h) In the following sections of the Credit Agreement, the term “Guarantor” shall include the “Additional Guarantor” mutatis mutandis in any place it appears in such section: subsection (b) of the definition of “Material Adverse Effect” in Section 1.1, Sections 1.2(k), 2.12(d), 4.14, 5.1, 6.1(c), 6.1(d), 6.2, 6.6, 6.8, 6.9, 6.10, 6.12, 6.14, 6.17, 6.18, 6.19, 6.20, 6.26, 6.27, 6.28, 6.29, 6.31, 7.2, 7.4(l), the last paragraph of Section 7.4, 7.5(a), 7.5(d), 7.6(a), 7.7, 7.10, 7.11, 8.13, 12.1(f), 12.1(l), 12.4, 12.5, 14.5, 14.13, 14.16, 15, 16, 17, 18.1, 18.7, 18.8, 19, 20, 21, 25, 27, 29, 33, and the form of Assignment and Acceptance Agreement attached as Exhibit C.

(i) By adding to the end of Section 3.5 the following:

“Notwithstanding the foregoing, if Borrower exercises the Extension Option, then commencing January 1, 2012 and on the first (1 ^st ) day of each calendar quarter thereafter, Borrower shall pay to Agent for the account of the Lenders as a prepayment of principal of the Loans an amount equal to $2,000,000.00, together with any amounts due pursuant to §4.8. Any payment of a release price pursuant to §5.3 shall not reduce any payments due pursuant to this §3.5.”

(j) By deleting in its entirety Section 5.3 of the Credit Agreement and inserting in lieu thereof the following:

“§ 5.3 Release of Collateral .

(a) Provided no Default or Event of Default shall have occurred hereunder and be continuing (or would exist immediately after giving effect to the transactions contemplated by this § 5.3(a)), the Agent shall release the Additional Mortgaged Property from the lien or security title of the Security Documents encumbering the same upon the request of the Borrower subject to and upon the following terms and conditions:

(i) The Borrower shall deliver to the Agent written notice of its desire to obtain such release no later than three (3) Business Days prior to the date on which such release is to be effected;

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(ii) The Borrower shall certify to Agent that no Default or Event of Default shall exist after giving effect to such release;

(iii) The Borrower shall pay all reasonable costs and expenses of Agent in connection with such release, including, without limitation, reasonable attorney’s fees; and

(iv) The Borrower or Additional Guarantor shall pay to the Agent for the account of the Lenders a release price, which payment shall be applied to reduce the outstanding principal balance of the Loans as provided in § 3.4, in an amount equal to Fifty Million and No/100 Dollars ($50,000,000.00).

Upon satisfaction of the terms and conditions of this § 5.3(a), the Agent shall promptly execute and deliver to Borrower and Additional Guarantor a release of the CH1 Mortgage, the CH1 Assignment of Leases and Rents and any UCC financing statements filed in connection therewith evidencing the termination and release of Agent’s security interest and lien in the Additional Mortgaged Property, and a release of the CH1 Guaranty, the CH1 Indemnity Agreement and the CH1 Indemnity and Guaranty Agreement all without the need for any consent from, or notice to, any Lender.

(b) Upon the refinancing or repayment of the Obligations in full, the Agent shall be entitled to release the Collateral from the lien and security interest of the Security Documents and to release the Borrower and Additional Guarantor, as applicable, provided that Agent has not received a notice from the “Representative” (as defined in §14.17) or the holder of the Hedge Obligations that any Hedge Obligation is then due and payable to the holder thereof.”

(k) By inserting at the end of the last sentence of Section 6.10 of the Credit Agreement “and for Additional Guarantor is 20-8495821” before the period.

(l) By deleting the introductory sentence of Section 6 of the Credit Agreement in its entirety and inserting in lieu thereof the following:

“Borrower, Guarantor and Additional Guarantor, as applicable, represent and warrant to the Agent and the Lenders as follows.”

(m) By adding at the end of Section 6.21 the following:

“REIT is the managing member of Safari Ventures LLC, a Delaware limited liability company, which is the sole member of Tarantula Interests LLC, a Delaware limited liability company, which is the sole member of Additional Guarantor. REIT owns (directly or indirectly) not less than fifty percent (50%) of the economic, voting and beneficial interest in Additional Guarantor, and Guarantor owns (directly or indirectly) not less than ninety-nine percent (99%) of (and REIT owns the balance of) the economic, voting and beneficial interests in Tarantula Interests LLC, free and clear of all Liens.”

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(n) By adding as new Section 6.32 to the Credit Agreement the following:

“§6.32. Contribution Agreement . The Borrower, Guarantor and Additional Guarantor have executed and delivered the Contribution Agreement, and the Contribution Agreement constitutes the valid and legally binding obligations of such parties enforceable against them in accordance with the terms and provisions thereof, except as enforceability is limited by bankruptcy, insolvency, reorganization, moratorium or other laws relating to or affecting generally the enforcement of creditors’ rights and except to the extent that availability of the remedy of specific performance or injunctive relief is subject to the discretion of the court before which any proceeding therefore may be brought.”

(o) By deleting in its entirety the introductory clause of Section 7 of the Credit Agreement and inserting in lieu thereof the following:

“Borrower, Guarantor and Additional Guarantor, as applicable, covenant and agree that, so long as any loan or Note is outstanding:”

(p) By deleting in its entirety the period at the end of Section 7.4(l) of the Credit Agreement and inserting in lieu thereof “; and”.

(q) By inserting as new Section 7.4(m) of the Credit Agreement the following:

“promptly after they are filed with the Internal Revenue Service, copies of all annual federal income tax returns and amendments thereto of the Guarantor.”

(r) By adding to the end of Section 7.4(e) of the Credit Agreement as new Section 7.4(e)(iv) before the semicolon the following:

“and (iv) an operating statement for the Additional Mortgaged Property for each such calendar quarter and year to date (such statements to be in form reasonably satisfactory to Agent)”

(s) By deleting in its entirety the introductory clause of Section 8 of the Credit Agreement and inserting in lieu thereof the following:

“Borrower, Guarantor and Additional Guarantor, as applicable, covenant and agree that, so long as any Loan or Note is outstanding:”

(t) By deleting in its entirety Section 8.4 of the Credit Agreement and inserting in lieu thereof the following:

“§ 8.4 Merger, Consolidation . Borrower and Guarantor will not, and will not permit REIT, Managing Member or Tarantuala Interests LLC, and Guarantor will not permit any of its Subsidiaries to, become a party to any dissolution, liquidation, disposition of all or substantially all of its assets or business, merger, reorganization, consolidation or other business combination or agree to effect any asset acquisition, stock acquisition or other acquisition individually or in a series of transactions which may have a similar effect as any of the

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foregoing, in each case without the prior written consent of the Required Lenders except for (i) the merger or consolidation of one or more of the Subsidiaries of Guarantor (other than Borrower or Additional Guarantor) with and into Guarantor (it being understood and agreed that in any such event Guarantor will be the surviving Person) and (ii) the merger or consolidation of two or more Subsidiaries of Guarantor (other than Borrower or Additional Guarantor); provided that no such merger or consolidation shall be permitted in the event Borrower, Guarantor or Additional Guarantor is in default of any of its obligations under this Agreement or any other Loan Document immediately before or would be after giving effect thereto.”

(u) By deleting in its entirety Section 8.14 of the Credit Agreement and inserting in lieu thereof the following:

“§ 8.14 Equity Pledges . Notwithstanding anything in this Agreement to the contrary, Managing Member will not create or incur or suffer to be created or incurred any Lien on any of its direct or indirect legal, equitable or beneficial interest in Borrower, including, without limitation, any Distributions or rights to Distributions on account thereof, other than to secure the Permitted Mezzanine Debt. Tarantula Interests LLC will not create or incur or suffer to be created or incurred any Lien on any of its direct or indirect legal, equitable or beneficial interest in Additional Guarantor, including, without limitation, any Distributions or rights to Distributions on account thereof. Furthermore, in the event of a transfer of the ownership interests in Borrower in accordance with the Intercreditor Agreement, the owner(s) or holders(s) of such interests will not create or incur or suffer to be created any lien on any such interest or permit any transfer of a direct or indirect interest in Borrower.”

(v) For the avoidance of doubt, whenever in this Amendment a term or provision of the Credit Agreement is said to include another term, the parties hereto intend that such term or provision as amended include both such terms as if the same were more fully and completely set forth therein.

3. Commitment Increase .

(a) Pursuant to the provisions of Section 2.11 of the Credit Agreement the Borrower hereby requests an increase in the Total Commitment from $100,000,000.00 to $250,000,000.00 pursuant to Section 2.11 of the Credit Agreement (the “ Increase ”).

(b) Certifications . In connection with the Increase, each of the Borrower, Guarantor and Additional Guarantor certifies that:

(i) As of the date hereof and as of the effective date of the Increase, both immediately before and after giving effect to the Increase, there exists and shall exist no Default or Event of Default;

(ii) As of the date hereof, the representations and warranties made by the Borrower, Guarantor and Additional Guarantor in the Loan Documents or otherwise made by or on behalf of the Borrower, Guarantor or Additional Guarantor in connection therewith or after the date thereof were true and correct in all material respects when made, are true and correct in all material respects as of the date hereof, and shall be true and correct in all material respects as of the effective date of the Increase, both immediately before and after giving effect to the Increase, as though such representations and warranties were made on and as of that date; and

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(iii) The principal amount of the Loan immediately after giving effect to the Increase will not exceed either (a) forty percent (40%) of the Appraised Value (as determined by the Appraisal of the Mortgaged Property delivered to Lender on the original Closing Date) of the Mortgaged Property as set out in the Appraisal or (b) such amount as will result in a “Debt Service Coverage Ratio” of at least 1.75 to 1.00 (based, for purposes of this calculation, on the “stabilized” Net Operating Income of the Mortgaged Property projected in the Appraisal approved by the Lenders); and

(iv) Borrower has paid all fees required by that certain Fee Letter dated February 10, 2009 between KeyBank and Borrower.

(c) New Commitments .

(i) Borrower hereby acknowledges and agrees that as of the effective date of the Increase and following satisfaction of all conditions thereto as provided in Section 2.11 of the Credit Agreement, Schedule 1.1 of the Credit Agreement shall be deleted in its entirety and Schedule 1.1 attached hereto shall be inserted in lieu thereof. The amount of each Lender’s Commitment shall be the amount set forth on Schedule 1.1 attached hereto and the Total Commitment under the Credit Agreement will include the Increase.

(ii) In connection with the Increase, (x)&nbs