Ts2019 64-bit The Correct Details

Discussion in 'General Discussion' started by Peter Hayes, Oct 16, 2018.

  1. Peter Hayes

    Peter Hayes Well-Known Member

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    "What will 64-bit do for Train Simulator?
    The introduction of 64-bit will essentially mean that Train Simulator will have access to all the available memory your computer has to offer. If you have lots of memory, 16 GB or more, then the software may be more stable overall as it will be less limited by the hard 4 GB limit (2 GB on a 32-bit computer) that all 32-bit applications are limited by."
    This is totally inaccurate, again you are confusing the Virtual Address Space VAS and Physical RAM and they are totally different.
    This is what I wrote for TS2016 and it applies to TS 2018:
    The Virtual Address Space and its relationship to Physical RAM.
    The Virtual Address Space (VAS) and Physical RAM have almost nothing in common, as long as there is enough physical RAM installed correctly so that data from the VAS can be used by the computer, ie the working set, then all is well. The VAS has nothing to with the “paging file” which is basically a hard drive extension of the physical RAM. The VAS does communicate to the RAM via the by transferring instructions from the VAS to the working set, but the size and speed of the RAM does not affect the VAS. The VAS is from the OS and RAM is hardware and the VS and OS communicated with the RAM via the cpu.
    Each time an application runs on a Windows (OS), Windows creates a new process and a new VAS for this process.

    I'll try to explain with a 32-bit app like TS2016* running in Windows (XP, Vista, Win7) the OS reserves 4GB of Virtual Address Space for the program to run in (this has absolutely nothing to do with how much RAM is installed). The reason for the VAS is if an app like TS2016 crashes, it does not bring down the whole windows OS as it would have done in earlier versions.

    Now running Windows OS 32-bit, Windows reserves 2GB VAS (aka kernel-mode VAS) for the system and 2GB for TS2016. However, if you have video card with say 512 MB VRAM you lose 512 MB off your 2GB VAS, leaving only 1.5GB VAS for TS2016 to operate in. To get around this in a 32-bit system only, the /3GB (userva=2560) switch is applied freeing up to 3GB VAS (NOT Physical RAM) to TS2016, but the video card will still pinch 512 MB. This is not without problems as the system has only got 1GB VAS to operate in and that can cause instability.

    Fortunately in a 64-bit OS a 32-bit app like TS2016* has access to a full 4GB of VAS and the video card uses only a tiny, tiny amount of that. So now TS2016 has the 4GB VAS to operate in it becomes less prone to crashing and Out of Memory errors.

    *TS2016 has a flag called ‘IMAGE_FILE_LARGE_ADDRESS_AWARE’ set so that it can use the full 4GB of VAS

    You can have 1GB RAM or 16GB Physical RAM, plus a 4GB paging file installed but TS2016 will still only have 4GB VAS tops in a 64-bit OS.

    So forget Physical RAM – it is not important as long as you have installed it properly and the correct amount for you OS version. It has very little impact on any crashes seen in TS2016.

    The problem is that you only have 4GB VAS and as the program like TS2016 (especially in the editor) runs the VAS becomes fragmented (VMMAP) and the contiguous space for TS 2016 to load into becomes less and less. Now once you reach a critical point (and even not having 1MB of contiguous space can cause this) the 32-bit app crashes. Nine times out of 10 the reliability monitor or event viewer will record a cx00000005 error the so called “memory mismatch”. Restarting TS2016 regularly will clear the VAS and make crashes less frequent.

    TS2016 does NOT crash due to a RAM issue, unless it results in a BSOD – then something else is very wrong.

    TS 2019 is a very different simulation. In 64-bit mode it can address up to 8 TERABYTES of VAS irrespective of how much RAM you have installed. That's why TS 2019 64-bit will be very stable, (but having extra Physical Ram installed will allow routes and scenarios to load and run smoothly). But the most important feature is the 8 TERABYTES of VAS.
     
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  2. SamYeager270

    SamYeager270 Well-Known Member

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    Peter Hayes Most people are not technical experts and frankly couldn't give a toss about the detailed nitty gritty which they won't understand anyway . Now there's a lot to be said for people being more tech savvy but that's a discussion for another time and place. DTG have simplified the explanation to make it as comprehensible as possible to non technical experts.
     
  3. mrsandman

    mrsandman New Member

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    Thanks Peter for the informative post, solid, well written, easy to read background posts like this are wanted. thanks again
     
    Last edited: Oct 17, 2018
  4. DeanO55

    DeanO55 Member

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    Thank's Peter, it's always nice to know your tech head is constantly on the ball. Thank's for keeping us up to date with what's what.
     

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