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AR# 14932

Install - How do I enable more than 2 GB of memory application support on Windows XP Professional?


For large devices and complex designs, my 32-bit Windows-based software tools encounter a 2 GB memory limitation. 

How can I work around this limit?


Windows XP Professional 32-bit

Note: 32-bit ISE applications on Windows XP Professional 64-bit can access a full 4 GB of memory.

Note: The switch mentioned below might severely affect your machine's stability.

Before enabling 3 GB support for Xilinx applications, read the Microsoft Knowledge Base Article #328269 at: http://support.microsoft.com/?kbid=328269

The standard Windows OS architecture limits the maximum memory available to a Xilinx program to 2 GB.

In Windows XP Professional, Microsoft created an option to support the ability of an application to address 3 GB of RAM.

Xilinx applications have built-in support for this option.

To take advantage of this capability, you must also modify your Windows XP OS to enable this feature, which requires that you modify your "boot.ini" file by adding a "/3GB" entry to the end of the "startup" line.

Please review the following information before using this switch:

Microsoft Bulletin Q17193, which contains information on "Application Use of 4GT RAM Tuning":

Microsoft Bulletin Q289022, which contains instructions for editing your "boot.ini" file:

For Windows Vista machines, see (Xilinx Answer 32052).
AR# 14932
Date Created 08/29/2007
Last Updated 12/17/2014
Status Active
Type General Article
  • ISE
  • ISE Design Suite