Okay, the clues so far:

 

Antilag helps the performance of, at least, certain Nvidia and Radeon cards.

DXTory, running concurrently with Flight, produces similar performance improvement on, at least, one Radeon graphics card and a card of unknown type.

A DVD copy program running in the background produces similar performance improvement on, at least, one Radeon graphics card.

 

My impression is that the majority of people, or at an rate all those with high end GPUs, are able to run the game smoothly. Whereas just a few of us are having problems with various degrees of stuttering etc. My guess is that we are experiencing this because our GPUs are not powerful enough to play the game smoothly. Apparently, Flight hands off more of the work to the GPU than previous versions.

 

The vsync on/off option does not do anything for me because frame rates never get up to screen refresh rate when playing the game on my system.

 

So, strange but fortunate that an external frame rate limiter can make such a big improvement in performance.

 

Has anybody experimented with the Set Render Ahead value? I left it at the default '2' but I noted that folks on the FSX forum are recommending it be set to '0'.

Hey trevorbee,

 

Regarding vsync:

In the Icon or RV-6, using the hat switch, pan horizontally while watching the framing of the windscreen; also try waggling your wings while looking straight ahead.

With vsync off I notice tearing of the vertical part of the framing and jerkiness while waggling. Cleaner with vsync on.

 

Jim F.

With vsync off I notice tearing of the vertical part of the framing and jerkiness while waggling. Cleaner with vsync on.

 

Hi Jim

 

Will give that a try when I get home this evening.

 

Cheers

Trevor

Hi Jim

 

I just did some tests with vsync off and on as you suggested. To be honest, I could see no difference either way. I had been running Flight with vsync off but now have it on and will see how it goes for a while.

 

Seperately, I tested with the Render AheadLimit value changed from 2 to 0 (as recommended on the FSX forum). That was a disaster - frame rates dropped right down and all the old stuttering problems came back. Changed it back to 2 and now running smoothly again.

 

Curiouser and curiouser.

 

Cheers

Trevor

Hi Trevor,

 

I rechecked and vsync makes a very noticeable difference on my Radeon card. I recalled seeing a reference to "Wait for vertical refresh" in the program to set up the card and so I tried different settings but I couldn't see where that had any effect. I tried to capture the discontinuity but it doesn't show up in the picture. I'd say that when you pan if the frame looks blurred but in line it's not a problem with your setup.

 

Jim F.