TZeer

Issue: With the Heat Blur effect on the A-10C. The CPU and GPU's will throttle down their performance when Heat Blur is active on the A-10C. Any time the plane is flying slower then ^260 knots the GPU and CPU will reduce their performance. Does not happen if the AI is flying the plane. Only when you are the pilot. Does not happen when flying the SU-25T. Do not have the other modules so have not tested them. In my case, the FPS will go down from ~100FPS and to about 50-60 FPS. When heat blur effect goes off, fly faster then ~260 knot, performance on GPU and CPU goes up. It's like there's put a maximum limit of how high the GPU's can go in performance. This is on a SLI setup. DxDiag.txt Performance Drop.trk

The engine might be old, but it's still pretty. What really kills it sometimes is the shitty optimization. * Heat blur effect, drags down performance even when your not looking at it. * Cockpit flood lights, 30-50 FPS loss by just turning on a light in your cockpit. It's shitty optimization or bad code. Period. * Water effects. Putting it on high making your FPS go all over the place. Even when your not even looking anywhere near water. Everyone is talking about EDGE, but if EDGE is as badly optimized as the current engine it wont matter.

Have it working perfectly with my 2x580GTX in SLI. But I have read there are alot of people struggling to get their 690 working properly, even in 3DMark.

Let me know how it goes. I have a friend that has the same card, but we are unable to get it working properly, not just in DCS, but other games as well. His GPU's will just not activate properly. It's like something is telling them to perform at maximum 40-50%. What kinda driver version are you using for the 690?

Updated first post with current findings and status.

Spot on SkateZilla!! Just tested it and your right. Taking off the heat blur effect removes the problem. Now the question is, why does the heat blur effect reduce GPU and CPU usage? Btw, did not see this behavior on the SU-25T. Is the bandwith of the GPU at it's limit? Memory controller full?

More testing. With speed lower then ~260 knots. The drop in FPS goes away if I go external view and zoom out. When I cross a certain distance everything goes up. When I zoom back in, everything goes down. Going from 130-140 FPS and smack down to 59-60 FPS. I don't think it is related to the blur, as the blur will come in effect as soon as you go full throttle. I was going full throttle from 180 knots, and the FPS did not go back up until I crossed the ~260 knot speed.

Also, activating your flood lights in the cockpit kills the FPS by ~50FPS Takes the FPS from 120-130 and down to 70-80. But if the plane is going slower then ~260knots, the FPS is already down to ~60FPS and you get no further drop by activating the floodlights.

Here is the track for the GPU/CPU usage drop. Also linking the performance screens. That behavior I have not been able to reproduce yet, haven't tried that hard yet either. But I suspect it's tied to something else. Test.trk

BREAKTHROUGH!! I can now start and stop the FPS drop at will. It looks to be tied to the FM of the A-10C. Every time I drop below 263 knots +/- a few knots depending on load-out or altitude (This one I havent figured out yet). The CPU usage and GPU usage drops. Get above it again and the GPU usage and CPU usage goes up again. I have not been able to reproduce it on a single 580 GTX. This can either mean it only happen to SLI setups. Or my graphic card is not powerful enough. Even with the drop in CPU usage and GPU usage on a SLI setup, the load will still be enough to tax my GPU at 100% and it will restrict the performance.

Will do :) If it was, it should have been happening when I did the same thing with the SU-25. Which it didn't. I don't have mirrors activated. Cockpit MFD resolution is at 512. Shadows are high, In my earlier tests it had no effect on my FPS on my setup. Water I took down to low, due to some strange FPS drops that came into play. My first post in this thread I show some screenshots where you don't see much difference, but the FPS drop is very noticeable. Reducing water to low, almost reduced that drop to nothing. Visible Range, yes, that has a very big impact on FPS. But, reason I kept testing was due to GPU usage and CPU usage going down when the FPS was going down. If you read my earlier tests you can see screnshots of my CPU and GPU usage during these tests. I even took away my overclock in the scenes where I had the least FPS. Removing almost 1 GHz of CPU power did nothing to my FPS. I was able to do some tests with a fellow squadron pilot last night. He had single GTX 680. We where unable to provoke the same GPU usage drop on his machine. So this might be a SLI issue. Would need another test first. Vlerkies sending you a PM :)

VRAM is never maxed out. Doesn't matter if I use high or low detail textures. And doesn't matter if I do it in populated area or flat boring landscape. And I just tested in the SU-25T, I can turn and jink that aircraft all over the place without getting the same effect. Rock solid 80-90 FPS over Tiblisi with Kuky's high.lua mod.

Yeah, but I don't see the point in the GPU/CPU pulling a "blackout" :smilewink: Those effect's are ingame. It has no influence on how the hardware should behave. When you get the drop depends on how hard and how long you hold the turn. I was able to provoke the drop even at 2,5 G. Not very much, but I was holding the turn for a short moment then. Or I can just break left/right and pull a 4,5 G turn instantly and get the drop. If anyone have some spare time to help me test something out I would appreciate it. I'm looking for people with either a AMD 7970 or Nvidia GTX 680 card, and high end i5/i7 CPU. Thanks

Update: Have not been able to do the PCI-E 2.0 vs 3.0 test. But found some other interesting things. Came back today to continue my testing, just to suddenly not have any GPU drop in usage while tilting my view....??? This was quite interesting. Specially since my FPS was constantly above 90 FPS. Started a SLI vs Non-SLI test at different resolutions: Lowest recorded FPS 1024x768 Non-SLI ~100 FPS SLI ~103FPS 1440x900 Non-SLI ~84FPS SLI ~103FPS 1920x1080 Non-SLI ~68FPS SLI ~95FPS 2560x1440 NON-SLI ~55FPS SLI ~95 FPS Important to note on the above tests. None of the cores on the CPU where ever taxed to 100%. Maximum average CPU usage was 29%. I must say, this is a lot better then my previous tests. But I was still curious why my FPS was suddenly so much better then the other day. Decided to fly around for a bit when suddenly out of nowhere my GPU/CPU usage and FPS dropped again. After a while they came back up again. Reason for the FPS drops turned out to be me pulling a tight turn!!!! YES!! I have not yet found out how to reset whatever I'm doing so the FPS get's back up again. Put I can now decrease FPS/GPU/CPU usage on command while flying by just doing either sudden pull or a right/left bank with my joystick. Every time I do this, the CPU/GPU/FPS goes down. In my case, I drop form comfortable 80+ FPS in cockpit, to 55 FPS. While flying over Tiblisi. Sometimes the effect resets itself after a short while. After my last attempt I have not been able to reset it. Only thing left to test is a disable/enable SLI again or restart computer. The following pictures are of my GPU's and CPU during the testing. As you can see, the time for it to reset varies. If you pull a gentle turn nothing happens. If you pull a hard-G turn the drop comes. If you just do a sudden movement on the stick, the drop comes. You can be flying straight and do a sudden left/right bank on the stick, and the drop comes.... Edit: Turned out I had to restart my computer for the reduction in GPU/CPU usage to go away after my last attempt. Was unable to provoke the drop by just pulling or sudden moves on the stick this time. But a high-G turn did the trick. And it doesn't matter if I do it above the city, turn toward the city, or just on a plain open boring place with nothing to see.

I have a few more tests to do. I'm gonna see if I can narrow it down even further. So far I have ruled out the CPU as the reason for my FPS drop. Have a fellow squadron member that have almost identical system as me, i7 3820. But instead of GTX 580, he is running GTX 680. Since this is a Sandy Bridge-E CPU we are still running PCI-E 2.0 and not PCI-E 3.0 as Ivy Bridge. This way we can at least rule out the PCI-E lanes as the reason.

Would be nice if ED could take a peek at this as well. Cause to be honest, this was not what I expected to find. But I'm a little happy as well, since GPU's are evolving faster then the CPU's at the moment. And with AMD and NVIDIA coming with a new generation. I'm gonna jump straight from GTX 580 and up to whatever they gonna cal them and get a nice boost.

Could be hard, since he's living in another country :) But I will replace my SLI setup with a more powerful single card setup when amd/nvidia release them. But so far all the tests I have done points toward that it's actually the GPU that is causing the major FPS drops. Either by some design/component in the cards that get utilized 100% that we can't monitor, or just plain horrible code inside the graphic engine. Here's another funny little thing I found as well. I don't now how many of you who run kuky's high lua mod for the rendering distance on districts. Anyway, I do. And when I replaced his high lua file, with the normal high lua file, my FPS didn't change. No increase in FPS. Which is strange, since I basically cut the distance from 20km and down to 10km....

I tried that, but it's only ok as long as I look straight. Look to the side and it's slideshow imo. Reason I do this is to find out if it's the CPU or GPU that is the bottleneck for the FPS drops. Normally people are saying it's the CPU. But all my tests says otherwise. Even though my SLI setup is not being used at 100% during the test, there seem to be something in the design of the card that is clogged up and making it impossible to increase the FPS. My goal is to get stuff running at 60 FPS so I can run with vsync on. Been able to do a test with a friend of mine, similar setups. But he had a GTX 690. He used my mission file, and we had identical options selected in the options. And he had over 90 FPS at the lowest. But when FPS dropped like it did for me, his GPU usage went down as well. This just confirms that it's actually the GPU that is whats holding back the performance, even though you wouldn't think it, when you look at the GPU load alone.

Update: After the last test I decided to test my theory. My CPU is normally overclocked to 4,6 GHz. If it is my CPU that is holding the performance back, my FPS should drop even more if I took away my overclock. If it's my GPU I should see no difference. I reduced my CPU down to 3,7GHz. Repeated what I have done earlier. And guess what? NO change in FPS. Nothing at all. Horizon with a full city, 55 FPS stable. So a reduction at almost 1GHz on my CPU had no difference at all on my FPS.

More data incomming!! :) So I disabled my SLI and did the same tests with just 1 x 580 GTX running. While looking straight down and at an area my FPS was ~120 FPS. When I looked towards the horizon with the city, my FPS went down to ~55 FPS. Now the interesting part. When I was looking straight down, my CPU usage was close to 100%, Meaning my FPS was held back by what the CPU was able handle. As I changed my view making more and more of the horizon and city visible. The CPU usage suddenly took a dump. But the GPU usage was still @ 100% At the same time the FPS started going down as more and more of the city came into view. 100, 90, 80 and at the end ~55 FPS. During that time the CPU usage did not change. That had already dropped like a brick when the FPS stated dropping in the beginning. Adding a second 580 GTX doesn't do much. It takes my FPS up to roughly above 60 FPS. A gain of less then 10 FPS. The other interesting part is that when running SLI, the GPU's also reduce load during this test (60% on each). So they should in theory have more power to do stuff. I also have not run out of VRAM. And as we can see on the CPU usage, there is plenty of CPU to play with. But adding 2xMSAA drops my FPS with a small amount. Why? There is more GPU to play with, there's CPU and there's plenty of VRAM. My thoughts right now: It's actually the lack of power/juice/whatever in the graphic card. Something that's not possible to measure by pure GPU or VRAM usage. I also suspect it's something that's shared in an SLI setup, since adding a second card doesn't do much. Kinda like VRAM. 1,5GB+1,5GB = 1,5GB VRAM When some new cards are getting released by AMD or NVIDIA, I'll be able to test this out.

I agree with you. If the CPU is no able to keep up, the FPS will be hit. But reason I made this post is that the CPU usage is not going up. It's actually going down, or not moving at all. And when I move my camera, and get those 100+ FPS, the CPU usage goes up as well. The GPU is at 100% usage. Turn the view around again, and BAM!! Average CPU usage goes down with almost 10%, GPU usage is down to 60% and FPS is down to below 50 FPS.... All the test where done on a clean map in mission editor. So nothing extra "behind the scenes" logic that's being calculated. Everything from OS to drivers and software is a clean install. My specs: 2x 580GTX in SLI i7 3820@ 4,6GHz 16GB Ram Win 7 on separate SSD drive DCS on separate SSD drive It's like everyone has accepted that DCS is such a monster to run for the CPU, that no one actually questions when you see some sudden FPS drop. "Oh, yeah, it's your CPU being a bottleneck" I have monitored everything from CPU average usage, single core usage, temperature on every core, GPU usage, memory usage, VRAM usage. And there is nothing, nothing at all that is pointing in the direction of the CPU getting a heavier load. Is there something deeper in the hardware that is getting clogged? Some really bad coding? Artifacts/bugs in the graphical engine? I would guess ED had some sort of debugging/raw code/monitoring tool to see what is actually going on in the background in scenes like this? What is reducing the performance? What makes the simulator drop by 40 FPS by just changing the angle slightly on how you view the world?

More screens and more strange FPS behavior. Flying level, nothing fancy going on. Flat and boring landscape, 87 FPS Here, almost the same place, just a few seconds before, 58 FPS A new one, nothing fancy going on. Just large space with nothing on. 52 FPS And the last one, behold, we actually got a small town/city in right corner. What's this? 96 FPS?? Whats up with this? LOL

More testing done :) Scenes, Textures, Visible Range, Shadows.... No change in behavior. Got more FPS. But the drop in FPS was still big. With Visible Range at low I actually got a drop of 40 FPS!!! Doing the same thing. Here is the funny part: Setting water to low reduced the drop considerable!! With 2560x1440 resolution everything on high, I got sudden drops at certain angles that took my FPS down to about 40 FPS. Reducing water to low, I'm constantly above 60 FPS. But the effect is still there. Turn my camera 180 degrees toward the airfield. And my CPU AND GPU usage goes up and I have over 120 FPS. Something is messed up when it comes to how water or whatever is handled. Also the flickering lines that suddenly came when the FPS dropped is gone as well. What hardware resource is used when water is displayed? What bottlenecking the performance?

Ok, some more info. If I turn my camera 180 degrees and look towards the airfield. My CPU average usage goes up to 20-25% and peaked at 29%, and my GPU usage went up to 100%. FPS @ 120+. All settings on high. So this confirms that both the GPU and CPU usage is going down for some strange reason. When CPU and GPU usage goes down, I also start noticing random lines, flickering on the screen. Just a fraction of a second. Which is strange. Cause it goes away when the GPU and CPU usage goes up.

Updated: 11.02.2013 These FPS tests started mainly due to my curiosity on why my SLI setup was not utilized more then it was. In this first post I will try to have the latest findings and results at the beginning so people can quickly see what have been done, and maybe help them along to get better frames in this awesome simulation. Some of these results might not be possible to reproduce if you are not using a powerful single GPU config/SLI or have a slow CPU. Issue: Unstable FPS, sudden drops while looking in a certain direction. If you are experiencing behavior similar to what is written below here together with the screenshots it can be the detail of water. In the screenshots below you can hardly see any difference. But the FPS speaks for itself. Solution: Reduce water details to low. Example: If I'm using my settings I have FPS at around 80-90 FPS. If I set water detail to high, the FPS can go as low as 35 at very special occasions. Not stable 35, but they jump up and down. So try and set the water detail to low (You wont see much difference at 12000 feet anyway :smilewink: ) Issue: Flying at speeds lower then ~260 knots will cause the CPU and GPU to reduce performance, and therefor loss of FPS. If you experience your SLI/powerful single card setup not not being used properly this might be the reason. When your A-10C moves slower then ~260 knots it generates a heat blur at the exhaust of the engines. For some reason when this happens the GPU and CPU cut down in performance. In extreme cases you can go from 120-130 FPS and down to 60 FPS for no other reason then your speed went under ~260 knots. An effect you normally don't look at unless you turn your head 180 degrees. It's not very often the A-10C moves at >260 knots with full tank and payload, so you might not have noticed it. Since it's been there all the time. But it really kills the performance on your SLI setup. Solution: Take off heat blur effect Issue: Activating flood light in cockpit reduces FPS by ~20-50 FPS If you turn on the green light that floods the cockpit, it will reduce your FPS with up to ~50 FPS. Depending on your setup. No solution yet Here's my current settings. With this I'm able to fly over Tiblisi with Kuky's high.lua mod and rocking 80-90FPS in daylight with no green cockpit flood lights :pilotfly: Link to Kuky's mod: http://forums.eagle.ru/showthread.php?t=71639 Textures: High Scenes: High Civ Traffic: Off Water: Low Visible Range: High Heat Blur: Off Shadows: High Resolution: 2560x1440 Aspect Ratio: 16:9 Monitors: 1 Screen Res. Of Cockpit Displays: 512 MSAA: 2x HDR: Normal Clutter/Bushes: 0 m (Havent tried increasing it yet) Trees Visibility: 15000 m Preload Radius: 150000 m Disable Aero Interface: Check Tree Shadows: Uncheck Vsync: Unchecked (For testing, normally on) Full Screen: Check Cockpit Shadows: Uncheck (Not tested yet) TSSAA: Uncheck (Not tested yet) My specs: i7 3820@ 4,6GHz - 580 GTX SLI - SSD - 16GB RAM - Win 7 I will not remove or edit any of the posts I have made in this thread so you can read along if you fancy. All updates and findings I do I'll put in the beginning of this post. **************************************************************************************************************************************************************************************************************************************************************************************************************** Been messing around a little bit and trying to find out why the FPS is behaving so strangely in DCS. So far I have no clue, hehe. This is the simple test I did. 1 unit in the middle of Tiblisi. Zoom out and pan around and monitor the FPS while having nVidia inspector and task manager up to monitor the behavior of my hardware. For this test I had vsync off. First screenshot. FPS at 57. Everything maxed out. Looks good. Next screenshot, and we get 46 FPS, a loss of 11 FPS. Whats different? All I did was change the angle a little bit. If I had moved it slightly more the FPS would go up again. So this is just in a very small narrow place I get this behavior. What gives? Here I reduced view distance to medium. FPS at 134. Really good. Again, change angle slightly, and we are down to 102 FPS. Thats a loss of 32 FPS just by changing the angle a tiny bit. Same thing here as well, if I moved it a little notch further, and the FPS would go up again. During this, the CPU load never changed. Average CPU load was at 15% max. Max load on one single core was maybe 40%. GPU load did change. But when I got those drops in FPS, the GPU load went down. Which would be normal if the CPU was the bottleneck. But I had no change in CPU load. It was constant. I have done other tests where I have seen CPU load go up while the GPU load have gone down. And it's a nobrainer that it's the CPU that is the bottleneck in those scenarios. But this behavior here, leaves me a little puzzled. Anyone have any good ideas?