http://blogs.msdn.com/hiltonl/archive/2007/04/13/the-3gb-not-4gb-ram-problem.aspxProblem statement: I just bought a system with 4GB of physical RAM in it. The BIOS posts 4GB, but Windows tells me that I have anywhere from 2.75 - 3.5GB of RAM. Where is the rest of my RAM? Summary: If you are running 32-bit Windows, you must live withen-USCommunityServer 2.1 SP1 (Build: 61025.2)http://blogs.msdn.com/hiltonl/archive/2007/04/13/the-3gb-not-4gb-ram-problem.aspx#2122185Sat, 14 Apr 2007 02:40:51 GMT91d46819-8472-40ad-a661-2c78acb4018c:2122185SQL Musings<p>Windows doesn't see 4GB. If you have a 32bit OS with 4GB of RAM, Windows can't see it all.I saw this...</p> http://blogs.msdn.com/hiltonl/archive/2007/04/13/the-3gb-not-4gb-ram-problem.aspx#2137189Sun, 15 Apr 2007 01:48:33 GMT91d46819-8472-40ad-a661-2c78acb4018c:2137189Steve Rowe's Blog<p>Interesting post by TabBlogger about why installing 4 GB of RAM on a 32-bit box doesn't actually give</p> http://blogs.msdn.com/hiltonl/archive/2007/04/13/the-3gb-not-4gb-ram-problem.aspx#2146233Sun, 15 Apr 2007 21:11:35 GMT91d46819-8472-40ad-a661-2c78acb4018c:2146233Gennady<p>In some cases, you can regain some memory (make it visible to &nbsp;Windows) by placing some switch in boot.ini. I don't remember the exact switch name, but in my particular system this changed the value shown by windows from 3GB to 4GB. On another system, however, it changed the value from 3GB to 3.5GB only.</p> http://blogs.msdn.com/hiltonl/archive/2007/04/13/the-3gb-not-4gb-ram-problem.aspx#2146318Sun, 15 Apr 2007 21:32:27 GMT91d46819-8472-40ad-a661-2c78acb4018c:2146318Larry Mastro<p>Very interesting. But what practical difference does it make to applications? I believe 32 bit Vista, like XP, allocates the lower 2G to apps and the upper 2G to the OS. If you have 4 physical G, then won't your apps still have the maximum (2G) available in physical RAM? I suppose Vista can run comfortably in ~1G of physical RAM. Any chance slow BIOS ROM gets shadowed into the high gigabyte of physical RAM?</p> http://blogs.msdn.com/hiltonl/archive/2007/04/13/the-3gb-not-4gb-ram-problem.aspx#2147092Mon, 16 Apr 2007 00:04:25 GMT91d46819-8472-40ad-a661-2c78acb4018c:2147092Gennady<p>You can give more memory to the application using /3GB switch in boot.ini, that will give more memory to the application and less to the OS, we use it for almost every 32-bit SQLserver. I am not sure how that works on Vista/Longhorn - Vista apparently does not have boot.ini at all.</p> http://blogs.msdn.com/hiltonl/archive/2007/04/13/the-3gb-not-4gb-ram-problem.aspx#2148027Mon, 16 Apr 2007 02:48:48 GMT91d46819-8472-40ad-a661-2c78acb4018c:2148027Larry Mastro<p>I believe the /3GB switch is only useful for applications that are specifically coded to take advantage of it, like SQL Server. Vista does not have boot.ini, but most of the same options can be set through the new boot configuration editor.</p> http://blogs.msdn.com/hiltonl/archive/2007/04/13/the-3gb-not-4gb-ram-problem.aspx#2158124Tue, 17 Apr 2007 02:37:31 GMT91d46819-8472-40ad-a661-2c78acb4018c:2158124John at myITforum.com<p>I&amp;rsquo;ve seen several asking about how much memory Windows Vista will use. MSDN has a great blog explaining</p> http://blogs.msdn.com/hiltonl/archive/2007/04/13/the-3gb-not-4gb-ram-problem.aspx#6970407Thu, 03 Jan 2008 21:18:18 GMT91d46819-8472-40ad-a661-2c78acb4018c:6970407PTaylor's WebLog<p>The best explanation of this I have yet found is here ; with this article as a supplement. This explanation</p>