Some findings about Open Rails and its CPU/GPU usage

[GoGoran]

Hi folks,

I am just getting started again with OR, so while this may not be news to anyone here, it is new and exciting for me.

I play with OR on a dual screen setup, 2 x 1280x1024, with OR only on one screen with 1280x1024. Standard settings.

OS: Windows7 Ultimate SP1, 32-bit
System: intel Core 2 Quad Q9400 (2.66GHz, 6MB L2-Cache), 4GB DDR2-RAM, Ati HD4350 with 512MB DDR2
Open Rails v1.2, standard options, simple physics model

I checked the usage of CPU and GPU with the help of the Windows Task Manager for the CPU as well as the tool GPU-Z (using the log to txt-file function) for the GPU.

At 2000m line of sight on the standard Northeast-Corridor Route, the CPU usage was always between 10 - 20% mostly. The GPU usage was 100% at all times and the video RAM usage was around 240 MB. GPU temperature was about 80°C (the card does not have a fan).

At 1500m line of sight on the standard Northeast-Corridor Route, the CPU usage was about the same, maybe a bit lower. The GPU usage was still 100% at all times but the video RAM usage dropped to around 150 MB. Oddly enough, the GPU temperature dropped to about 75°C now, presumably due to less communication with the V-RAM.

So, my conclusions for now:

1 - Reducing the line of sight decreases V-RAM usage a lot (and vice versa) and helps control GPU temperatures as well for whatever reason. It does not, however, increase the frame rates, seemingly not at all.

2 - My CPU is way overpowered for OR as it looks like, at 10-20% use during playing. Of course this is one of the bare-bones standard MSTS routes with a standard train from 2001, so newer routes and trains will probably need more horsepower.

3 - My GPU (Ati HD4350) is the limiting factor for now. I should exchange it for a newer, better, faster one, also with more V-RAM.

What do you think?

PS - All in all I am pleased with the new version of OR v1.2 for now, it looks and feels good and works flawlessly thus far.

[mikeebb]

I think that GPU is what I had originally in my desktop (came with the donated motherboard & CPU). Replacing that, even with something that's low-end by modern standards (at least 2GB RAM, such as nVidia GTX 750ti or 1050) will give you a vast improvement in OR performance. It will, however, have a fan so it will be noisier that what you have.

If Task Manager is showing only 10-20% CPU when running, that's another sign that something else is the bottleneck. In my X9650, CPU runs about 50% because the GTX750ti takes more data and handles it more quickly.

Another good diagnostic tool is the debugging F5 (Control-F5 iirc - not at my OR computer right now) in OR itself. Page through it until you get to the performance graphs - if you're redlining the graphics task and everything else is more or less idling (as is probably the case), you need a better GPU. And regardless of the tools, if you have a Core2 Quad and aren't seeing at least 30-40 fps in the F5 display for most routes, you have a GPU problem.

EDIT: Also, you should consider using a 64-bit Windows version and get more RAM. Many Core2 motherboards can handle up to 8GB RAM (using 2GB sticks, usually). And 4GB is still plenty to run 64-bit Windows anyway. 64-bit allows you to run ORTS with Large Address Aware (LAA) turned on, which allows use of all free virtual memory (up to 4 GB) rather than limiting you to 2GB as 32-bit Windows does. There is a workaround for 32-bit Windows that allows user space of up to 3 GB, but it has side effects on system stability that might not be worthwhile (worth trying, but keep a good backup!) - google 3GB tuning. The downside of 64-bit is that if you use very old (DOS and Windows 3) games you will need to find another way (like using DOSBox) - the NTDVM (for running 16-bit software) is only included with 32-bit versions.

[GoGoran]

Thank you for your valuable input and advice, mikeeb!

I will avoid switching to 64-bit since many old MSTS installers require 16-bit support and I also depend on many programs which need unsigned driver support - a thing that is only possible with the 32-bit version of Windows 7. I tried hacking it and signing the drivers myself but not joy ... Besides 32-bit Windows in general runs much faster and snappier than the same system as a 64-bit version, with the possible exception of Windows xp x64 Edition.

And I got a patch which allows me to use more than 3.5GB of RAM with my 32-bit Windows. In fact, i got other PCs of the same type with 6GB and 8GB RAM installed, which is usable in its entirety by Windows 7 32-bit thanks to this patch. The 2- or 3GB-limit for single threads remains, of course. And i must not update it anymore, since Microsoft closed the possibility for this hack in 2016 or so ... so past-2014 no updates for me anymore. The 4GB-patch is more important to me than the latest updates.

I got several largely identical PCs, all Fujitsu-SIEMENS P5730, which support up to 16GB of DDR2 RAM ... The most I got is 8GB in one machine, but I will try to find some 4GB DIMMS soon. But DDR2 is scarce and expensive on ebay ... The fastest CPUs supported are Core 2 Quad Q9650 or ore 2 Duo E8600 ...

[ftldave]

I will avoid switching to 64-bit since many old MSTS installers require 16-bit support and I also depend on many programs which need unsigned driver support - a thing that is only possible with the 32-bit version of Windows 7. ...

True about 16-bit programs and their requirements, but unsigned drivers don't require hacking, just an Advanced Startup setting for installation.

5 Methods to Load Unsigned Drivers in Windows 7, 8 and Vista 64-bit (x64) - similar procedure available in Windows 10, too.

[GoGoran]

True about 16-bit programs and their requirements, but unsigned drivers don't require hacking, just an Advanced Startup setting for installation.

5 Methods to Load Unsigned Drivers in Windows 7, 8 and Vista 64-bit (x64) - similar procedure available in Windows 10, too.

I tried all of those methods before and none of them would work.