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Ray Proudfoot

Cause of stutters in FSX found and greatly reduced

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My new system should run FSX pretty well but since building it I've been bothered by stuttering but finally tonight I think I've pinpointed what's causing it.The purpose of anti-aliasing is to smooth the jagged edges primarily when running at lower resolutions. In the days of 800*600 or maybe 1024*768 they were very apparent and by setting AA to 4x it greatly reduced these jaggies albeit with a lower frame rate.My new system feeds a 24" display running at 1920*1200. Now you might argue that at such a high resolution there's no need for AA - the resolution is higher than the much vaunted 1080 of high definition TV.But without AA there is a degree of shimmering of buildings and that reduces the overall quality of the view. So I have been setting it to 6X - the highest available. This gets rid of the shimmering but significantly I've discovered it introduces stuttering. Even with such a powerful graphics card asking it to smooth edges at 6X at such a high resolution is clearly working the card harder than it's happy with.I've reduced AA to 4x and things are signiicantly better. The best way to see this is to switch to full forward view (no panel visible), slew up to around 500ft AGL and press the forward arrow key until a speed of 66kts is achieved. Place your aircraft in a fairly well built up area and observe how smoothly the scenery passes below.I've done this with 6X AA and 4X AA and the difference is remarkable. There are still some pauses or stutters but they are far fewer than before and the overall smoothness is much improved.Whether this will work for you I don't know. If you're running at lower resolutions you may need your current AA setting but experiment with different AA values and things may improve for you as they have for me.Maybe you've already discovered this for yourselves but I was always under the impression that modern cards could handle any amount of AA at any resolution. Clearly there is a sweet spot and maybe you can find it on your system.Cheers.

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Ray,Your card is capable of running up to 16X AA (at a heavy price on system performance).The following modes of AA are available for the 3870X2:2x Box (2x samples)2x Narrow-Tent (4x samples)2x Wide-Tent (6x samples)4x Box (4x samples)4x Narrow-Tent (6x samples)4x Wide-Tent (8x samples)4x Edge-Tent (12x samples)8x Box (8x samples)8x Narrow-Tent (12x samples)8x Wide-Tent (16x samples)8x Edge-Tent (24x samples)16x Box (16x samples)16x Narrow-Tent (24x samples)16x Wide-Tent (32x samples)For FSX I am currently utilizing 4x Box with temporal anti-aliasing enabled. FYI going from 4x Box to 16x Box on my system will cut FPS in half.

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Hi Mike,I have already tweaked my FSX.CFG and BUFFERPOOLS is set to PoolSize=12000000.The point I was trying to make was that reducing AA from 6X to 4X has considerably reduced stutters. I don't see how any other settings are relevant to this particular change.

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Sargeski,Why would I want to increase AA to 16X if the penalty was so severe?It's currently set to 4X Box where it will remain. Temporal AA is disabled.Cheers,

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>Sargeski,>>Why would I want to increase AA to 16X if the penalty was so>severe?>>It's currently set to 4X Box where it will remain. Temporal AA>is disabled.>>Cheers, You wouldn't lol....the only reason I pointed out the available settings for the 3870X2 was because in your above post you stated "So I have been setting it to 6X - the highest available."I was not sure if you were aware that higher settings are available and did not want would be 3870X2 owners to think that max AA was limited to 6x for a 3870X2.For anyone using Nvidia cards and thinking of the 3870X2 4x Box on the Radeon is pretty much comparable with 8xs on the Nvidia cards. Albeit much prettier!! ;)

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Ray I am glad to see that the stuttering was caused by AA...I was concerned that it was because of the "uploading data between gpu's" issue that Holger mentioned in the other thread. I see that's not the case!Great news!I'd guess that if you lowered resolution (not that you would want to) you could run higher levels of AA before the stuttering kicked in.Also I would guess that we may be seeing a bit of driver immaturity here, although 1920 res, a lot of AA will push hard on a vid subsystem.RhettAMD 3700+ (@2585 mhz), eVGA 7800GT 256 (Guru3D 93.71), ASUS A8N-E, PC Power 510 SLI, 2gb Corsair XMS 3-3-3-8 (1T), WD 150 gig 10000rpm Raptor, WD 250gig 7200rpm SATA2, Seagate 120gb 5400 rpm external HD, CoolerMaster Praetorian

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Hi Rhett,<>No, of course given that the whole purpose of AA is to address the limitations of low resolutions. in fact I may try 2X. Least is always best when manipulating an image.The 8.4 drivers are due out soon but whether FSX will benefit is a moot point. It's not one of the high profile games but I'll keep my fingers crossed.For now I'm pleased to have eliminated most of the stutters with a simple adjustment of AA.

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Hi Sargeski,<>Point taken. It's only when you go into the Settings option in ATI TT that the Box option becomes available. In the simplistic AA sub-menu the max there is 6X.I can't see anyone who buys this card running at resolutions as low as 1024*768. It's for large displays only really. For 1024*768 a single 3870 would suffice.

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Thats bad news.I thought the 3870 was supposed to solveall our (nvidia) display problems.What is it like with AA on in FSX only and not in the driver?gb.

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Why is it bad news? I found by reducing AA the stutters were greatly reduced.I did try setting it in FSX but it's just an on/off setting so how do you choose what level you want? 3rd party applications are always better as they allow different settings.I've not seen FSX with a nVidia card so I can't comment on the image quality (or lack of). As far as I'm concerned the ATI has superb image quality.

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You'll be hard pushed to find any card that offers a stutter-free performance. There are just too many variables to consider. An occasional stutter will always be present. That's been the case since FS went to a Windows platform and had to share resources.I'm not sure what you wanted to point me to in a 4 page dialogue started 18 months ago. Graphics cards have changed a lot since then as has hardware generally. If you google "stutters" and "FSX" you'll find numerous hits and all different setups.The point of my original post was to point people's attention to the AA setting and that if set too high may introduce stutters. I never claimed my or any card would give stutter-free performance.nVidia cards will probably stutter too and they have driver issues which the ATI doesn't. The image quality of my 3870X2 is excellent and should certainly be on your shortlist assuming you'll be running at 1920*1200 otherwise a 3870 may sufice.

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Ray & Bob et al...did you get the Cat 8.4s?Boosted my 3870x2 back to ~ 13,500 (default) 3DMark06 (~50% greater than 8.3s). What this does for FSX performance idk yet. :-PRob

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Hi Rob,Yes, updated last night. 3DMark06 score is back to what it was with the 8.2 drivers. No issues so far with them. Just completed a flight from EGLL up to Glasgow and the scenery looked stunning. Towering cumulus also looked good but frame rate suffered when flying through them.I don't think frame rates in FSX were too different with any of the recent drivers.

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