I have just ordered a matched pair of ram to make my total 4mb.I have read the supplied advice that comes with the PMDG MD11 regarding extra ram.Does this advice still hold good?It says to download from (http://www.ntcore.com/4gb patch.-php) the patch and runit navigating to the FSX.exe file (after backing it up).They then say go into MY COMPUTER but I think that they mean boot.iniand add /3gb to a particular line. This is all clear and I will do this. Can anyone tell me1.What does running the 3gb.exe file actually do as on many other posts on this forumtalk about going into the boot.ini as above but no menetion of the 3gb patch utility.2.Also whereas the PMDG says add /3gb to the file the other posts usually also addsomething like 3gb/Userva=2560. what does this extra piece do?Is it needed?Some of them also add 'fast detect' as well.I would be very grateful if someone could clarify this for me.I am running XP Professional with SP3 and FSX SP3.Thank youDavid

I have just ordered a matched pair of ram to make my total 4mb.I have read the supplied advice that comes with the PMDG MD11 regarding extra ram.Does this advice still hold good?It says to download from (http://www.ntcore.com/4gb patch.-php) the patch and runit navigating to the FSX.exe file (after backing it up).They then say go into MY COMPUTER but I think that they mean boot.iniand add /3gb to a particular line. This is all clear and I will do this. Can anyone tell me1.What does running the 3gb.exe file actually do as on many other posts on this forumtalk about going into the boot.ini as above but no menetion of the 3gb patch utility.2.Also whereas the PMDG says add /3gb to the file the other posts usually also addsomething like 3gb/Userva=2560. what does this extra piece do?Is it needed?Some of them also add 'fast detect' as well.I would be very grateful if someone could clarify this for me.I am running XP Professional with SP3 and FSX SP3.Thank youDavid

Hi David,I am not a computer expert by any stretch but in real simple terms and clarity of understanding let me explain it this way.A computer deals with two types of memory they are physical RAM like that which you have purchased and virtual memory that which the computer uses as in (for sake of understanding) software or its system programming. Virtual memory is really address space and sometimes even called address space. Basically every time the system wants to transfer data around it needs an empty street or address to send the data down. If you do not have an empty street you are in trouble (out of memory error). Virtual memory or addressing has nothing to do with the amount of physical RAM that you have in your system. For example you could have 12GB of physical RAM and still run out of virtual memory. Conversely you could have 2GB of physical RAM and still expand the virtual memory via the 3GB switch. In other words you do not need 4GB of RAM to benefit or use the 3GB switch.Many people confuse this address space or virtual memory with RAM memory. It is so much easier to understand the two once realized they are two completely separate and different things. The 3GB switch only affects the virtual memory has nothing (little) to do with physical RAM.32 bit operating systems like XP-Pro do not have as much virtual memory as a 64-bit system such as Windows7-64 or XP-64. The real fix for out of memory issues is therefore a 64-bit operating system. Even after applying the 3GB switch a 32-bit system will not have anywhere near the same amount of virtual memory as does a 64-bit system. Not only will a 32-bit system not have the same virtual memory but the 3GB switch will actually deprive the system of virtual memory and can cause serious operating issues.The 3GB switch is therefore not recommend unless you are experiencing out of memory issues that would otherwise make your system unusable. The 3GB switch is a band-aid and was originally intended for testing purposes only. The 3GB switch is not a tweak or a performance enhancer. A 64-bit operating system is the correct fix.1. Continuing along the lines of simplicity; a 32-bit system has a maximum of 4GB of virtual memory to deal with. The system will use 2 of those GB for the system and allow the other 2GB to be used by programs like FSX. If FSX tries (and often does) exceed 2GB of use you will get an out of memory error (OOM). This is because of the virtual not physical memory.2. The 3GB switch tells the system to give 3GB of virtual memory to programs and only keep 1GB for the operating system.a) Here we have a problem. Out of the 1GB that we have now left to the Operating system, the operating system will reserve some of that memory for the video card leaving now less than the 1GB of memory that we thought that we had for the Operating system. On a 768MB video card this would leave very little memory for the Operating system.3. To compensate for things like the video card we do not want to give full 3GB to programs. We can then trim the 3GB switch to give more back to the system memory (virtual memory). To do this we use the USERVA command. 512MB is a reasonable figure to give back to the Operating system so we should set a USERVA of 2560. This means we are giving 2560MB to programs and 1536MB back to the operating system. In other words not taking the full 3GB for programs.FASTDETECTShould be left in the boot ini as it causes the operating system to skip loading of certain devices at boot.Noexecute=optin is another command that should be left in as it plays a roll in PAE.See my post here as to how to add the switch but again you really need get yourself into a 64-bit operating system when you can. Only add the switch if you must.http://forums1.avsim.net/index.php?s=&...t&p=1650028See also: http://technet.microsoft.com/en-us/sysinte...s/bb963892.aspx

Hi David,I am not a computer expert by any stretch but in real simple terms and clarity of understanding let me explain it this way.A computer deals with two types of memory they are physical RAM like that which you have purchased and virtual memory that which the computer uses as in (for sake of understanding) software or its system programming. Virtual memory is really address space and sometimes even called address space. Basically every time the system wants to transfer data around it needs an empty street or address to send the data down. If you do not have an empty street you are in trouble (out of memory error). Virtual memory or addressing has nothing to do with the amount of physical RAM that you have in your system. For example you could have 12GB of physical RAM and still run out of virtual memory. Conversely you could have 2GB of physical RAM and still expand the virtual memory via the 3GB switch. In other words you do not need 4GB of RAM to benefit or use the 3GB switch.Many people confuse this address space or virtual memory with RAM memory. It is so much easier to understand the two once realized they are two completely separate and different things. The 3GB switch only affects the virtual memory has nothing (little) to do with physical RAM.32 bit operating systems like XP-Pro do not have as much virtual memory as a 64-bit system such as Windows7-64 or XP-64. The real fix for out of memory issues is therefore a 64-bit operating system. Even after applying the 3GB switch a 32-bit system will not have anywhere near the same amount of virtual memory as does a 64-bit system. Not only will a 32-bit system not have the same virtual memory but the 3GB switch will actually deprive the system of virtual memory and can cause serious operating issues.The 3GB switch is therefore not recommend unless you are experiencing out of memory issues that would otherwise make your system unusable. The 3GB switch is a band-aid and was originally intended for testing purposes only. The 3GB switch is not a tweak or a performance enhancer. A 64-bit operating system is the correct fix.1. Continuing along the lines of simplicity; a 32-bit system has a maximum of 4GB of virtual memory to deal with. The system will use 2 of those GB for the system and allow the other 2GB to be used by programs like FSX. If FSX tries (and often does) exceed 2GB of use you will get an out of memory error (OOM). This is because of the virtual not physical memory.2. The 3GB switch tells the system to give 3GB of virtual memory to programs and only keep 1GB for the operating system.a) Here we have a problem. Out of the 1GB that we have now left to the Operating system, the operating system will reserve some of that memory for the video card leaving now less than the 1GB of memory that we thought that we had for the Operating system. On a 768MB video card this would leave very little memory for the Operating system.3. To compensate for things like the video card we do not want to give full 3GB to programs. We can then trim the 3GB switch to give more back to the system memory (virtual memory). To do this we use the USERVA command. 512MB is a reasonable figure to give back to the Operating system so we should set a USERVA of 2560. This means we are giving 2560MB to programs and 1536MB back to the operating system. In other words not taking the full 3GB for programs.FASTDETECTShould be left in the boot ini as it causes the operating system to skip loading of certain devices at boot.Noexecute=optin is another command that should be left in as it plays a roll in PAE.See my post here as to how to add the switch but again you really need get yourself into a 64-bit operating system when you can. Only add the switch if you must.http://forums1.avsim.net/index.php?s=&...t&p=1650028See also: http://technet.microsoft.com/en-us/sysinte...s/bb963892.aspx

Hi GaryThank you for your reply. Unfortunately I cannot update to a 64bit system at present.I have to make the best use of what I have. I don't have oom problems but are just trying to make my MD11 and747 run smoother. Have I wasted my money by buying more ram?The reason I did so was from PMDG as follows:-FSX Memory Use in Windows XP:Generally speaking, we recommend that users run this simulation with asmuch available memory on their machine as possible. It should be notedthat FSX is naturally limited to only using 2GB of available ram, but canbe modified to take advantage of greater physical ram on machines thathave more than 2GB available.Warning: We recommend the following only for advanced users who arecomfortable modifying their computers for optimal performance.Download the 3GB EXE Patch utility from the following link:Are they mistaken in recommending more physical ram?Also are they correct in saying that FSX will not recognise more that 2gb. of ram?Regards,David

Hi GaryThank you for your reply. Unfortunately I cannot update to a 64bit system at present.I have to make the best use of what I have. I don't have oom problems but are just trying to make my MD11 and747 run smoother. Have I wasted my money by buying more ram?The reason I did so was from PMDG as follows:-FSX Memory Use in Windows XP:Generally speaking, we recommend that users run this simulation with asmuch available memory on their machine as possible. It should be notedthat FSX is naturally limited to only using 2GB of available ram, but canbe modified to take advantage of greater physical ram on machines thathave more than 2GB available.Warning: We recommend the following only for advanced users who arecomfortable modifying their computers for optimal performance.Download the 3GB EXE Patch utility from the following link:Are they mistaken in recommending more physical ram?Also are they correct in saying that FSX will not recognise more that 2gb. of ram?Regards,David

Hi David,I am not in a position to debate what PMDG said or may have said. They have a staff of ex-NFL football players on their team and I am too wee of a man to combat them. Probably their information is just dated.I will say that first and for most that adding 4GB of RAM was not a waste and is what I would have recommended in your case assuming you have an older mother board and processor not capable of running 6GB of DDR3 RAM. i.e. you are not running an i7 processor.What you write

Hi David,I am not in a position to debate what PMDG said or may have said. They have a staff of ex-NFL football players on their team and I am too wee of a man to combat them. Probably their information is just dated.I will say that first and for most that adding 4GB of RAM was not a waste and is what I would have recommended in your case assuming you have an older mother board and processor not capable of running 6GB of DDR3 RAM. i.e. you are not running an i7 processor.What you write