Out of Memory (OOM) Errors

Part One

While I’ve had my share of CTD’s (Crash to Desktop) in FSX over the years, I only recently began experiencing the dreaded Out of Memory (OOM) errors which plaque many.    As a result, until I started experiencing the OOM’s I really didn’t know much about them, nor what truly caused these to happen.  Likewise, I was also mis-informed about how to prevent them from happening.  What?  I’m running out of memory?  Time to go to the hardware store and buy more RAM.  WRONG!!!!!

Let’s break this down…..

FSX is a 32 bit Windows application.  While I (and many others) suggest running Windows 7 64-bit OS on your Flight Sim computer, FSX is still a 32 bit application.  Even with FSX installed on a Windows 7 64 bit computer, the maximum amount of VAS (virtual address space) available for FSX (and all the goodies installed for FSX) is just 4 GB.  But hold the presses….you have 6, 8 or more GB of RAM.  What is going on?  Again, due to FSX and its 32 bit restriction, the best you can expect is a max of 4GB of VAS.  Any more will trigger the OOM error and bring much frustration to your FS experience.

Now if you are running FSX on a Win 7 64 bit OS, consider yourself lucky. If you were running FSX on a 32 bit OS the best you would have is 2GB of VAS (3GB if tweaked).  To my knowledge, there are no tweaks to get any more than 4GB in the 64 bit OS scenario.

There is a ton of knowledge published by many wonderful flight sim enthusiasts regarding these OOM errors and how best to prevent them from happening.  Perhaps one of the best I’ve read is Kosta’s Flight Simulation World blog site.  The link to his specific article on FSX, OOM and Addon VAS Usage is here.

Again, I’ve been flight simming since the early 1980’s and have been an FSX user since day one of its release.  I’ve been running FSX on a Windows 7 64-bit OS computer with 6GB of RAM for over 3 years and I only began experiencing OOM errors.  So what was my tipping point?  Before I tell you what ended up being the straw that broke the camels back, allow me to give a brief history of the last 30 days.

For perhaps the past six months or so I’ve been saying to myself that I felt it was time to do a full and complete rebuild of my FSX machine.  I’d been having a variety of issues (mostly performance issues) with the machine which had been running for about 3 years on this build.  However, being the CEO of a relatively new VA, I just didn’t want to take the time away from flying to do a full reinstall.

I purchased the PMDG T7 about six weeks ago and was starting the process of learning to fly this beautiful aircraft.  I read the manual and I watched a few great Youtube videos.  The time was ready for me to make a flight from KDEN to KDFW.  Yes, a short-haul flight in a long-haul aircraft.  But I was limited on time and familiar with both airports…so figured it was a good first flight.

With exception of dragging the tail on take off, the flight was uneventful until I reached about 30 miles out of KDFW.  I began hearing a dinging sound which I had never heard before.  In my mind I’m trying to remember if I read anything in the PMDG manual about some type of audible warning.  I had no visible errors on the T7.  OK…no worries I’ll land at KDFW and then investigate what I did wrong to cause the dinging bell.  Then just a few minutes later….I received my very first OOM error message and FSX shut down.  Bummer…..

Remember, I had never experienced an OOM error before and with some of the other issues going on with my FSX machine…I decided the time was now to do a full reinstall of EVERYTHING.

When I build or rebuild my FSX machine, I follow the very sound advice outlined here in Nick’s FSX Bible for installing FSX.    So after spending a couple of days getting Windows 7 setup and getting FSX installed and the add-ons, I was ready to once again take flight.  But I also wanted to take the cautious approach and I made very good notes on what I installed and in what order. The PMDG T7 was one of the last payware aircraft I installed and was one of the last I got around to test.

As vAL (my virtual airline) continues to grow, we will expand and have plans to use the T7 to expand our cargo operations outside of North America.  We will probably offer a freeware paint version of our aircraft and offer the PMDG payware version.  In anticipation (still a few weeks out) of adding the T7, I needed to resume my practice in this awesome aircraft. So I loaded up another short flight (KDEN to KDFW) just like before and started my journey.  Success.  I landed in KDFW with no issues.  Over the next few days I completed many other flights all over the US in many different types of aircraft (payware and default/freeware) and had no issues.

One other point I want to make.  I love add-on scenery.  I have just about everything in Orbx North America catalog and have all the FSDT US airports and also now own the Orbx FTX Global.  My new FSX build really makes all the airports come to life and regardless if I’m flying VFR or IFR, low and slow or high and fast, it all looks good.  I’ve really been pleased with the effort I put into the new build.

On Saturday, I completed a flight from KDEN to KMIA (default FSX to default FSX airport) in the PMDG T7 with no issue.  However on Sunday I decided it was time to fly from KDEN to KLAX (default FSX airport to FSDT payware airport).  The departure from KDEN was uneventful (no tail drag) and as I was approaching KLAX (about 30 miles out) I began hearing that blasted dinging sound.  KLAX was landing west to east and as I made my turn to final out over the Pacific, OOM ERROR!  DOH!!!!

How was this possible? Why did this happen?  Is it PMDG’s fault?  Most importantly, what must I do to fix this from happening?

I began reading and learning about OOM’s.  Just about everything I read was telling me things I really didn’t want to hear.  Suggestions such as disabling scenery I’m not using.  Why?  Why would I need to do this?  I don’t have these issues with any other aircraft.  I was starting to regret my PMDG purchase.  But I forced myself to keep reading.  To keep learning.

Because I so enjoyed flying the PMDG T7, I was willing to start moving sliders, backing AI traffic down and disabling scenery.  I made a few small adjustments and began another flight from KDEN to KLAX. Boom….same place…OOM. Geez…. Really???

Oh, before I forget.  I did install the Process Explorer software which is mentioned on Kosta’s blog site.  Even with the tweaks I mentioned above, I was still maxing out VAS on approach into KLAX.  More cuts would be needed.

I turned AI traffic down to almost nothing.  I turned off ActiveSky weather and used FSX weather to setup a flight on a clear day.  Finally I deactivated ALL add-on scenery with exception of FTX Global and KLAX.  I once again departed KDEN and headed west to KLAX.  I performed the same approach as I had done the two previous attempts and made my turn out over the Pacific.  On final I was watching the VAS and it was creeping up, up, up.  Just as the T7 touched down on runway 07R the VAS hit 4GB and the dinging started.

While I was successful at getting the aircraft parked and FSX shut down without the OOM error.  What this was telling me was I would never be able to fly a long-range route and probably not be able to fly from payware airport to payware airport.  I really didn’t like these terms….But I continued to turn down the sliders and made one more attempt.  BINGO…I was able to fly from KDEN to KLAX without the OOM dings and my VAS stayed around 3.5 GB.  But it was rather boring looking outside.  I guess this is what it would be like if I wanted to fly the T7.

Now let me just quickly say that I do not blame PMDG.  While the PMDG T7 appears to be the only aircraft that pushes me over my VAS limit, this is not PMDG’s  fault.  Remember, FSX is a 32 bit application with restrictions as I outlined in the beginning of this blog post.  Should PMDG NOT have pushed the envelope as they did with the T7?  Some may say PMDG should not have…but I say…Push it baby!!!  It’s the only way we’re going to move past FSX.  But this is another story.

I will tell you that I’m not satisfied with what I must do to fly the PMDG T7.  I’ll tell you what I’ve done to resolve the issues in part two in the coming days.  Stay tuned….

Until next time…

Happy Flying!!!


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