Widescreen Gaming Forum

Apology first: The following will probably only make sense to IL-2 owners. :)

Hello, I have this weird problem in IL-2 that only happens when I run the sim in Perfect mode. If I run in Excellent mode all is fine and I get an average of 54-58 fps. In Perfect mode I get about 40-45 fps, which is to be expected, HOWEVER the display behaves as if I was getting 5-10 fps at most, that is to say, it is jerky to the point of unplayability.

Now the funny thing (in a sad way) is, in Excellent mode the fps will vary greatly when, for example, I fly over a big city at low altitude: I see the average fps moving from 60 to 20 and back, but still the display remains fluid enough that it stays playable. In Perfect mode the little "jerks" are always present, irrespective of the number of fps displayed by the sim.

This is at a resolution of 3840 x 1024, with a pair of GeForce 8800 GTX in SLI, under Vista 32-bits.

First of all, did anybody experience anything like that? And second, I'm trying to determine if the problem is one of driver/configuration/stupid user or whatnot, or rather if it is simply that the amount of detail on screen brings my videocards to their knees. That second option seems somewhat doubtful, I would think a pair of 8800 GTXs could chew the IL-2 engine for breakfast, but with the insane number of pixels generated at my resolution, I'm not quite sure. I do not quite know what it is with Perfect mode that would put such an increased load on the videocards.

Any opinion very welcome.

FT

It´s a known issue using SLI/CF (any multigpu system), called ´microstuttering´. Frames are there, but there are not generated at regular intervals (fe, if you have frames at ms 10,15,20,...,80,85,... 120,130, ...)

It strongly dependant on fps (only perceptible bellow X fps). For ex, if you have 60fps, it may behave like 60fps, but with 45 fps behave like 20fps.

Haaa, thanks very much MrCrowley. Always good to know I'm not the only one suffering from some weird computer anomaly !

So it would mean even buying newer more powerful cards would not guarantee solving the problem, but it might alleviate it? After doing a search for microstuttering and IL-2 / Oblivion it seems most of the forums postings I found were mostly from the 2007 era. I'm hoping this indicates the problem is lessened with newer cards?

Then the question would be, I suppose, would it be better to invest in one supermegacard rather than 2 in SLI, if I decided to solve my current problems by the expedient solution of buying new stuff.

FT

So it would mean even buying newer more powerful cards would not guarantee solving the problem, but it might alleviate it?

Exactly

I'm hoping this indicates the problem is lessened with newer cards?

Really not. Newer cards are more likely to maintain 50+ fps, which usually is the hot spot for microstuttering, but is only about pure performance. And with people using powerhouses as 295gtx for 19x12 and less or so (295gtx counts like two cards in sli), there are not many people noticing it.

Then the question would be, I suppose, would it be better to invest in one supermegacard rather than 2 in SLI

SLI is useful if you know (reviews with benchmarks on the net) you will have 50-60 min frames with a configuration similar to yours. If not, a monogpu system will be more reliable.

Thanks for all those bits of expertise.

Since I see that problem mostly in IL-2, could that be in any way related to the fact that my nHancer profile for that sim uses Split Frame Rendering instead of Alternate Frame Rendering ?

FT