I recently got an interesting explanation on why x64 is more interesting when your system has more than 4 Gb of memory.
The background is the size of the memory.
An x86 server system can manage a maximum of 4 GB of memory. This limits the addressable memory space for Windows server 2003 systems to 4 GB. (This is true for all 32-bit operating systems). With 2 GB reserved for the operating system by default on 32-bit Windows, only 2 GB of memory remains for SQL 2000 or SQL Server 2005 x86. You can increase this amount to 3 GB by setting a /3GB switch in a Windows BOOT.INI. In order to use more than 4 GB of memory AWE must be enabled. AWE is a set of memory management extensions to the Microsoft Win32 API that allows SQL Server x86 to address memory beyond 4 GB. Using AWE, applications can acquire physical memory as nonpaged memory, and then dynamically map views of the nonpaged memory to the 32-bit address space. AWE enables SQL Server 2000 and 2005 x86 to address larger amounts of data. Now, this is old news, everybody knows that.
BUT!
Although AWE makes execution of memory-intensive applications possible when otherwise impossible, AWE imposes overhead, adds initialization time, and can face performance challenges under various processing conditions. The use of AWE in a x86 environment is only for data caching so plan caching, sort space, and lock memory are still limited to 2 GB of memory in x86!!
These issues are eliminated on the x64 platform when directly addressing memory as AWE is no longer necessary. In x64 environments you are no longer limited to 2 GB for memory for plan caching, sort space, and lock memory. For any Dynamics - NAV implementation that will use more than 4 GB of memory for SQL Server, a x64 is recommended.
The expanded lock memory available when utilizing SQL Server 2005 x64 would be very beneficial if you plan on using the “Always Rowlock” database option in Dynamics - NAV as you could exceed the 2 GB of lock memory limit that exists on x86
I thought this info would be useful for everybody 
Dear all,
Recently, I got this information from Microsoft, which is generally known, but never put together into a nice overview.
Here is an overview of the buildnumbers of service packs and updates, together with a link to their KB articles.
The naming of the updates is not always applies concequently. E.g., update 1 for 4.0 SP3 is in many cases called "the Platform Release for Microsoft Dynamics NAV 4.0 SP3" to accomplish Vista compatibility. I also included more information about update 4.
Updates overview – 3.70.B – 5.0
|
Released Version |
Update |
Build |
KB Number |
Prerequisites |
|
3.70.B |
|
19516 |
|
|
|
|
Update 1 |
19868 |
890640 |
|
|
|
|
|
|
|
|
4.0 |
|
19365 |
|
|
|
|
Update 1 |
20942 |
890551 |
|
|
|
Update 2 |
21871 |
908918 |
Update 1 |
|
|
|
|
|
|
|
4.0 SP1 |
|
21666 |
|
|
|
|
Update 1 |
21990 |
913523 |
|
|
|
Update 2- NODBC |
22373 |
912791 |
|
|
|
Update 3 |
22363 |
915455 |
|
|
|
|
|
|
|
|
4.0 SP2 |
|
22100 |
|
|
|
|
Update 1 |
22611 |
919407 |
|
|
|
Update 2 - NODBC |
22851 |
921893 |
|
|
|
Update 3 |
23099 |
922695 |
|
|
|
Update 4 - NODBC |
23460 |
927113 |
Update 3 |
|
|
|
|
|
|
|
4.0 SP3 |
|
23305 |
|
|
|
|
Update 1 |
24080 |
931841 |
|
|
|
Update 2 - NODBC |
|
Not released |
|
|
|
Update 3 |
24219 |
933727 |
Update 1 |
|
|
Update 4 |
24449 |
936602 |
Update 1 |
|
|
|
|
|
|
|
5.0 |
|
24199 |
|
|
Update 4 for 4.0 SP3
Update 4 for 4.0 SP3 has been released as KB 936602. The following problems have been fixed in Update 4: · Error message when you try to back up a large database in Microsoft Dynamics NAV 4.0: "The network path cannot be found" · When you restart the computer or the server, Microsoft Dynamics NAV Application Server does not close the session. · When you design a MenuSuite, the OK button may be unavailable in the Item Creation dialog box even if you have completed all fields. · When you run NAV Application Server in a debug mode without using any parameters, a memory leak may occur. · After you change the properties of the Frame control in a form, the changed properties do not work as expected. · When the length of a filter string is longer than the underlying field length, Microsoft Dynamics NAV Application Server may stop responding. · When a primary key contains 250 characters, Microsoft Dynamics NAV 4.0 may stop responding if this primary key is used in a record reference. · When the related records in the main form are updated, sub-form records that contain references to the main form are not automatically updated. · When all menu shortcuts are hidden, Microsoft Dynamics NAV 4.0 may stop responding. Therefore, you cannot hide all menu shortcuts. · When you use a pipe symbol (|) as a separator in a dataport, the value in some fields may not be cleared before these fields are updated. · After you change the CalcFormula property of a flow field in a non-compiled table, Microsoft Dynamics NAV 4.0 may stop responding. · When you import an .xml file that contains data that includes an ampersand (&), an extra space appears before the ampersand. · After you change the value of a key group, the changed value does not affect the connected tables. · If a filter contains a two-digit number, the filter does not work as expected. For example, a filter that contains "1..12" does not work. However, a filter that contains "1..9" works as expected. · When you save a report to an .html file or to an .xml file, Microsoft Dynamics NAV Application Server may ignore the properties of the report. Important note: You must install Update 1, KB 931841 before you can install Update 4.source: Microsoft