Today I am testing DX10 again because I really WANT to use it with the upcoming A2A C172R Trainer: it has awesome VC shadows! This made me dig into DX10 once more and this time I really want to succeed.

 

I had a few problems with DX10 in the past: one was slower loading textures but that problem is simply solved by the C172R itself... because it is a LOT slower than my current default plane, the Lancair Legacy.

 

Another problem was that vsync didn't seem to work well. I am using full screen mode and I have it forced in FSX.cfg but during all my tests 9 out of 10 times I got VERY annoying tearing. Well, because today I am determined to get DX10 working properly (I am even thinking about lowering my holy autogen a notch to Very dense) I tested and tested and suddenly found out what was wrong...

 

Vsync ONLY works during the FIRST flight after I booted my PC...!!!

 

So whenever I stop a flight and decide to run FSX again WITHOUT rebooting the PC, I get terrible tearing! Now this isn't a problem at ALL for me because I already am developing a habit of preparing a flight (planning etc.) and then rebooting the PC before I actually start the flight. This discovery will certainly help making that a habit, but I am just curious what is happening here. I mean, it IS a bit odd that vsync stops working after restarting FSX, isn't it? Or is this a well known occurance...?

Found the answer thanks to this post from Paul J,:

 

http://forum.avsim.net/topic/416988-vsync-in-dx10/#entry2759383

 

I still had ForceFullScreenVSync=1 in my cfg (as I said in my OP I forced vsync because I thought I needed to do so with DX10). After removing that line I can restart FSX as much as I want and still have vsync!

.......I still had ForceFullScreenVSync=1 in my cfg (as I said in my OP I forced vsync because I thought I needed to do so with DX10). After removing that line I can restart FSX as much as I want and still have vsync!

 

@Jeroen

Well, that's funny. I've this parameter all the time like you had without any problems. I removed it and can't see any difference or any strange FSX behavior.

 

@Paul J

During doing these checks I accidentally found a recommendation of NickN for this parameter ForceVsync=True in the [Display] section.What's about this parameter and does it have any conjunction with the ForceFullScreenVSync=1 parameter in the [Graphics] section?

 

Spirit

Don't know, Spirit, however - forcing vsync from within FSX loses between 3 and five frames.

 

Much better that the GPU driver does it. Note - I haven't read all of Nick's latest how-to's, but 99% refer only to DX9 - and DX10 responds differently to many - even, perhaps all of the settings controlled by the drivers, or set within the fsx.cfg.

 

 

Don't know, Spirit, however - forcing vsync from within FSX loses between 3 and five frames

 

Full screen or windowed mode?

Full screen, Rendi, I don't know about frame loss in windowed mode, as I don't fly in windowed mode. I only use it to allow screen access to other program icons - like TrackIR, EZCA or FSGRW - that sort of thing. I would expect that there will be a loss, anyway, as I believe the monitor has a refresh rate that communicates with the GPU somehow, in order that the two are coincident. Refresh rate on an LCD monitor is not quite like a CRT monitor, and there's some mechanism which goes on which controls this, and setting vsync anywhere else will compromise that situation. Nvidia has the "1/2 Refresh Rate", with "Standard", and with 30 set in FSX. The GPU then attempts to keep the screen refreshes as close as possible to that rate. I set mine at 31 in FSX, and see 30 most of the time. In some cases it doesn't always quite work, but then one just adds "DisablePreload=1" into the [Main] section, and voila' - Vsync!

@Paul J

Ok, about FPS loss that's an argument which convinces me and I also do your trick with FPS locked at 31 in FSX to get a more stable 30 FPS.

Thanks

Spirit

 

 

 and I also do your trick with FPS locked at 31 in FSX to get a more stable 30 FPS.

Interesting to know! - I do find it works in some small measure, and I wonder how many others have thought about this?  I just considered that if the GPU is trying to "keep up" with a 30 - it might hit that figure a little more often if it was trying for 3, and it appears to... hmmm.  

 

Great minds think alike..   :lol: