VAS usage with XP11?

[be77solo 125]

Well, to be precise: VAS is active and works with 64 bit programs, but outside of the 32 bit area it doesn´t contain any usefull user information.  In 64 bits its limit is now 128 TB.

 

So, I have to chuckle, who's going to be the first to max out 64 bits and need more???  And will I still be able to see the screen or even alive haha

[FlyIce 354]

If I remember correctly, it takes about 20 years for us to go from 1MB to say 128GB max ram on PC today. So from 128GB to 128TB may not take as long as 20 years.

[Paraffin 2,197]

If I remember correctly, it takes about 20 years for us to go from 1MB to say 128GB max ram on PC today. So from 128GB to 128TB may not take as long as 20 years.

 

It may not, although to the extent any of this is graphics-related, there is a limit to how far you can go in pixel resolution on a big screen (or in VR) before you're just wasting pixels. An 8k monitor or the equivalent in a VR headset may top out what anyone really "needs" in resolution. 

 

Of course, that kind of thing has been said before, so who knows. Maybe the next step is a direct implant to the visual cortex, and we'll need something higher than our eyes can resolve.

:wink:

[MarkSC 122]

I flew in Spain today with HD mesh, Pilot2ATC, xEnviro and the CRJ-200.  Settings all high to max.  X-Plane 11 used 3GB of RAM. The system used well under 6 GB.  I just don't see any way that the normal user would exceed 16 GB unless flying in an extreme custom scenery area like NYCX.

[sizziano 172]

I flew in Spain today with HD mesh, Pilot2ATC, xEnviro and the CRJ-200.  Settings all high to max.  X-Plane 11 used 3GB of RAM. The system used well under 6 GB.  I just don't see any way that the normal user would exceed 16 GB unless flying in an extreme custom scenery area like NYCX.

 

Nope, I will always be using at least 10GB even in the middle of nowhere.

[johnman 7]

Regarding VAS - All Windows Programs use VAS, With a 32bit OS, all Programs Running Share 4gb Virtual Address Space . With a 64bit OS a 32bit Program can have up to 4gb of its own Virtual Address Space . I would be interested to find out How a 64bit Program, Running in a 64bit OS actualy uses Virtual Address Space ?? - Johnman

[Paraffin 2,197]

Regarding VAS - All Windows Programs use VAS, With a 32bit OS, all Programs Running Share 4gb Virtual Address Space . With a 64bit OS a 32bit Program can have up to 4gb of its own Virtual Address Space . I would be interested to find out How a 64bit Program, Running in a 64bit OS actualy uses Virtual Address Space ?? - Johnman

 

VAS isn't a term I've ever heard used in X-Plane, even when it was a 32-bit program. That's Microsoft Flight Simulator terminology, and I wish we could avoid it here.

 

Every new version of Windows ramps up the amount of RAM it can use, and we're nowhere near the theoretical limits for a 64-bit architecture. Hardware is the bottleneck. Here's where we are right now on Windows 10, and the amounts are lower on Windows 7 (remember X-Plane supports Mac and Linux too, and I don't have those numbers):

 

Windows 10 Enterprise 2TB

Windows 10 Education 2TB

Windows 10 Pro 2TB

Windows 10 Home 128GB

 

X-Plane 10 and X-Plane 11 will currently use somewhere in the neighborhood of 8 to 32 GB of RAM depending on what scenery you're running, like the RAM-intensive free UHD terrain mesh. 

 

The X-Plane page for recommended system requirements states that you should have 16-24 GB RAM or more for the best (recommended) experience with the simulator. They're not kidding. You'll use it, if you have a strong enough system that can run UHD terrain and complex city and airport files. Plus, some overhead for any new plane models with complex systems that appear during the XP11 product cycle.

[alpilotx 505]

I flew in Spain today with HD mesh, Pilot2ATC, xEnviro and the CRJ-200.  Settings all high to max.  X-Plane 11 used 3GB of RAM. The system used well under 6 GB.  I just don't see any way that the normal user would exceed 16 GB unless flying in an extreme custom scenery area like NYCX.

If your RAM usage is constantly below 4 GB with XP11 and - supposedly - HD Mesh Scenery v3, then you might need to re-check if your HD Mesh Scenery v3 installation works at all (because this very low RAM usage might be a hint that it is NOT working)!

 

There are instructions which help you to check out if things are working as expected:

• http://www.alpilotx.net/downloads/x-plane-10-hd-mesh-scenery-v3/#How-to-know-if-the-installation-was-correct

[anden145 2,285]

Well... it's not really that hard to understand.

 

In a 32-bit OS, the maximum allowed addressable memory is utilizing 32-bits - which means, 4 GB of addressable memory addresses - since the highest number you can write with 32-bits is (storage wise) 4 GB. Think of FAT-32 which can't handle files over 4 GB in size - same principle... A 32-bit application running on a 32-bit OS, can potentially assign 4 GB of memory - however, since the OS can't handle/understand memory over 4 GB (so it doesn't matter if you have 16 GB of memory in a computer running 32-bit OS - it still won't see more than 4 GB), the maximum allowed addressable memory for an application in a 32-bit OS is around 3,5 GB - since Windows reserves some memory for the OS itself.

 

When upgrading to a 64-bit OS, the allowed addressable memory is expanded to 128 TB. However, 32-bit applications (or threads) are still contained within the 4 GB limit. Some applications, then launches multiple threads - which each have 32-bits of assignable memory addresses available (or 4 GB of memory) - per thread.

 

A 64-bit application has expanded the addressable memory to 128 TB (per thread) - just like the 64-bit OS has. So a 64-bit application could potentially max out a 64-bit OS, and you would get an OOM - provided you have 128 TB of memory available. Which I don't think many people have... 

 

That's the way I understand it, anyway...  :smile:

[Guest-475 81]

 I would be interested to find out How a 64bit Program, Running in a 64bit OS actualy uses Virtual Address Space ?? - Johnman

IIRC, every program (or better process) is using VAS, no matter what the combination of 32/64bit is (OS/application).

The process "sees" it's VAS, while the OS is responsible for mapping this VAS to the  physical memory. Of course the VAS on 64bit OSes can be as large as 128TB.

 

OOMs are (and will always be)  possible if the PC has less RAM than what is requested by the sim, no matter if we are running 64Bits or not. Or let's call them OORs (out of ram), because I guess the OS will then start mapping part of the VAS to the pagefile, which is something you's probably want to avoid for performance.

[johnman 7]

Thanks Anders ! - Johnman  B)

[Longranger 148]

 I would be interested to find out How a 64bit Program, Running in a 64bit OS actualy uses Virtual Address Space ??

This is rather simple. Many programs have to open multiple files at the same time, but in reality they don´t really need free access to the complete file. They only need small windows. But if the process would have to do its own window mapping it would be complicated. So the operating system uses a trick. It gives you virtual addresses. In theory you have the complete file on access. In reality you don´t see the complete files, instead the operating has a small list that tells it address a1 to a2 are file x, address a3 to a4 are file Y and so on. it gets your address loads a small segment into the RAM.

Sounds complicated, but don´t forget that this is in fact business as usual for the OS. In reality you have several levels of cache in the processor and if the real memory is tight the OS writes parts of it to the harddrive.

So the amount of VAS can be multiple times bigger than the real amount of RAM.