GPU memory full, consequences?

[Pe11e 812]

So I took the plunge, started migrating to payware airports in P3D v3. After years in FSX with default airports, I think it is the time to bring realism one step higher. I have some amount on PayPal collected during the previous months, and I want to get at least 10-15 excellent hubs for flights in Europe. I already bought Aerosoft's Zurich v2 few months ago, bought yesterday ORBX Southampton and Arlanda, and tested all three, working flawless, fps around 70 in Bonanza. Now, when I was testing and slewing around the airports, gpu memory usage was over 1.8gb and that was without MyTraffic! I have GTX 960 with 2gigs of ram, and although there were no stutters and hickups/missing textures during testing, I thought that could be some serious problems when on final with the NGX and MyTraffic?

 

In general, what will happen if GPU memory is full? Stutters? Crashes? Higher VAS usage? Black textures?

 

I'm not ready to switch to gtx970 with 4gigs, and I will not buy the rest of the airports on my list before I test every possible situation.

 

 

Thank you!

[DaveCT2003 1,820]

Generally speaking, you don't have to worry about your GPU memory.

 

What can be an issue is an OOM (Out of Memory) error, which occurs because 32 bit programs (such as FSX/FSX:SE/P3D) run in an area of memory limited to about 3.5GB of RAM.

 

Anything which loads into that memory (Flight Simulator program, Addon Aircraft, and Scenery) will eat up that available memory.

 

I pretty much use nothing but payware aircraft and large airport payware scenery and I (like others) don't have OOMs as we reduce the memory footprint.

 

There are several very informative topics on preventing OOMs here in the AVSIM forums and I encourage you to seek them out as anything I write here is only going to repeat the terrific advice these threads contain.  One of the best is by PMDG and you can read it HERE.

 

But I can give you a very brief introduction:

 

1. Ensure you aren't using the maximum settings for your slight simulator graphics settings.

 

2. Only load the payware or memory intensive freeware scenery that you will actually use for your flight. Many of us use an excellent Freeware program called SceneryConfigEditor to Activate or Deactivate scenery for our flights.  Note that you can have scenery installed, it's only when it's activated that it will consume memory.

 

I wish you the best for Happy Flights!

[Pe11e 812]

Thank you Dave for detailed explanation.

 

I already know all about OOM although I've never seen one in FSX, even with the NGX and payware airports. There were some close situations with 300-400mb left, but no OOM.

P3D v3.2 is known for managing VAS much better than FSX, freeing up VAS on fly, so I'm not afrain of OOM in P3D. I know that some users are reporting OOM errors even in v3, but I'm trying to save some VAS with disabling airport traffic, hi-res textures, lowering autogen, disabling airport sceneries that I will not use during the flight, etc.

 

I'm still pretty interested what will happen if GPU memory is completely full? I don't have an idea what will happen?

[hjsmuc 393]

Correct me please if I am wrong but my understanding is that once the GPU memory is full textures are being swapped to RAM which slows down the process. If this was not the case I wonder why the top GPU's have more than 4GB of memory.

[pmb 5,137]

I am not a hardware expert, however, as far as I know the system will acces main memory (RAM) areas if the RAM on your card is exhausted.

 

You may also want to know that the GTX 970 only has 3.5 GB fast memory on board, the rest is considerably slower (as far as I know independent of the maker, it's a "feature" of the architecture). 

 

Actually I own an EVGA 4GB GTX 970 for P3D and I am happy with it.

 

Kind regards, Michael

[Bert Pieke 7,584]

Windows was designed to use all the available CPU and GPU memory and fall back to hard disk if CPU RAM filled up  (paging).

 

There should be no visible effect for the user other than reduced performance.

 

We, Flight Simmers, are so obsessed with performance that we try to have extra CPU and GPU memory available at all times, but that is a choice, not a requirement..

[hjsmuc 393]

 

 

We, Flight Simmers, are so obsessed with performance that we try to have extra CPU and GPU memory available at all times, but that is a choice, not a requirement..

 

Very well said, Bert. I am currently experimenting with an 8GB card to find out what, if any, difference this amount of GPU RAM makes. 

 

I am not a hardware expert, however, as far as I know the system will acces main memory (RAM) areas if the RAM on your card is exhausted.

 

Exactly, that's why I think GPU RAM is important.

[Pe11e 812]

Thanks chaps.

 

Can't say nothing more until I do my first fully loaded test flight with the NGX + FS2CREW + FTX Global + Vector + OpenLC EU + FsPassengers + MyTraffic at 10% (with AirTrafficManager) and ASN with the latest tweaks (disabled multiple visibility layers) and of course payware airports. Fingers crossed.

 

BTW I have 8gigs of RAM onboard and I think it will be sufficient if my GPU is drunk lol. Only, I truly hope so that performance will not drop considerably during that time.

[jimmynes 7]

 

 

Actually I own an EVGA 4GB GTX 970 for P3D and I am happy with it.

 

How does it perform with ai traffic?

[pmb 5,137]

How does it perform with ai traffic?

I Use UT2 with very low settings (radius etc.) I don't see any issues with the graphics card. Accoding to my (poor) understanding, AI traffic is more of a burden for the CPU than for the GPU, though. I loose 2 fps  when traffic kicks in on a heavy hub like KSFO.

 

The real burden is 4xSGSS, which it copes with while the former GTX760 had to struggle. (Keep in mind this is a special setup with a hardware panel and no 2D/3D panel on display, though.)

 

Kind regards, Michael