Hello. Recently LFS has started acting up on me by dropping down to extremely poor framerates on my Radeon HD3850 (down from 60-100 steady to 15 or worse). I think I've traced the problem back to enabling 8X AA as I'm not able to reproduce it with any other AA settings. Anyone else experience this problem?

The whole thing may have started after a driver update recently but I'm not sure which one as I don't play too often and only noticed just the other day. Both Catalyst 8.11 and 8.12 have the same problem though.

Setup:
Q6600 @ 3GHz
Radeon HD3850 256MB with Catalyst 8.12
4GB RAM
Vista 64

Could it be a card issue? I did have a quick google but couldn't see anything.

Have you tried using something such as a driver cleaner and then re-installing the 8.12 Catalyst drivers, and if that's not working, maybe go back to a driver back-dating 8.11 (Guessing 8.10 LOL)

I'm running on 8.11 on a 2900HD Pro and that works on 8x AA, so it could just be your card/driver combination.

I haven't been fiddling too much with it yet. Figured I'd check if anyone else had the same problem before completely disassembling my system.

Oh btw, have you tried using temporal AA?

Not sure if the 3850 has smoothvision, but try going to 4x AA and selecting the 'wide tent' filter. (If your card has the feature). That gives 8x AA, without actually selecting 8x. Maybe that can work.

Quote from S14 DRIFT :

That gives 8x AA, without actually selecting 8x.

It also blurs everything considerably compared to the pure 8X box filter. Unacceptable for picky bastards like myself.

But you got me onto something, it only happens if I select 8X AA from inside LFS. If I override from the driver it works normally.

Well glad you got it sorted, remember to turn it off when you go on Crysis or somethiing or your PC will freeze.

Quote from S14 DRIFT :

Well glad you got it sorted, remember to turn it off when you go on Crysis or somethiing or your PC will freeze.

Oh yes, been there done that.

While overriding is workable, it's still rather annoying to have to do it that way. I'll see about reporting the problem to ATI or something as I doubt this has anything to with LFS. It's hard to enable AA wrong. I'd like to hear from someone with similar hardware to rule out hardware failure though.

I have the hd 2600 pro and with 8x aa enabled my frame rate would dive from anywhere between about 40 down to about 12, resulting in what i like to call 'slideshow from hell' type gameplay together with the glitchy sound that goes with it for maybe a second or two, this used to happen fairly frequently and was annoying me for ages.

Despite me having very different computer specs to you, a slower CPU, a lot less ram, etc.. my similar issue with higher aa settings could kind of relate to yours.

All i did was put the aa down to 2x. With a little messing around with the internal graphics settings of lfs itself i have got it looking pretty much as smooth as it was and i can now hold a stable rate of about 55 fps.

EDIT: i see its already solved, damn my slow brain!

I used to have to user drivers to over-ride the AA a while back. Randomly fixed itself ><

That sounds very similar, yes. Even a HD2600 should be able to handle 8X AA in LFS (Heck, even my old 7600GT almost did it), so I doubt it's a lack of power in your case.

Weird I haven't experienced it before though. As I said, I haven't been playing much recently, but I can't remember ever having these problems until maybe a few weeks ago.

Quote from S14 DRIFT :

I'm running on 8.11 on a 2900HD Pro and that works on 8x AA, so it could just be your card/driver combination.

Just as a thought, could my problem be that my drivers are too new?
Im using the hd2600 pro (512mb AGP) using the newest 8.530 drivers and i am just thinking that maybe, despite these drivers being supposedly ok for my card (it took me ages to find an agp patched version) that they could somehow be in conflict with something in the lfs graphics setup. I was running a nvidia fx5500 (256mb) before my upgrade and i was achieving the same fps, if not marginally better performance with that much more underpowered card, although i didny have as many adjustable settings. Hell, i was holding a rock solid 25 fps using a pre-historic mx440 before that!

lol I thought I was the only one having problems with the 2900HD. It always overrides the in game settings and goes to no AA by default. I have a lot of ram but maybe it is the CPU that keeps me at 50 fps at 2X AA.

You could just be running low on memory on the card, 256MB is not that much for 8x AA if you are using large screen resolutions.

thats true i'm running 1650x1050 but any other resolution looks distorted.

Quote from Kegetys :

You could just be running low on memory on the card, 256MB is not that much for 8x AA if you are using large screen resolutions.

You make an excellent point. I run 1920x1200, so that's certainly a possibility. It it was right on the edge with memory usage before, a small change in the driver could easily break it. Wouldn't that show up in the texture memory counter inside LFS though? Right now it hovers around 50-60 MB IIRC, but that number may not include the framebuffer size?

Anyway, I'll try some lower resolutions later and see if that works.

Quote from wien :

Anyway, I'll try some lower resolutions later and see if that works.

Yup, that did the trick. When going down to 1680x1050 all is well.

I don't quite understand where all that memory is going though. If we do the math, assuming no compression and that 8x AA requires 8 times the framebuffer (does it?), I get a framebuffer of 1920x1200x32x8 + depth-stencil buffer 1920x1200x32x8 which means 2x70MB = 140MB. Add to that the 60 or so LFS uses for textures, and we're still a healthy bit shy of the 256MB the card has onboard.

At first I thought Aero might be hogging some memory in the background, but turning it off makes no apparent difference. Hmm, memory fragmentation combined with changes in the memory management inside the driver perhaps?

Oh well, guess I'll just have to make do with 4X AA then.

In case anyone cares, it turns out I'm an idiot. A few months back I rearranged the innards of my computer to make room for a new disk. Apparently the PCI-E slot I moved my graphics card to only has 4 of 16 lanes wired, as opposed to 16 on the other two slots. D'oh! I did of course know this at one point, but I never connected the dots when LFS started stuttering. I just reseated the card in one of the 16 lane slots, and performance is back to normal.

I must say I'm really impressed with the how much PCI-E bandwidth improves performance when an application spills out of the on-board video memory. I really had no idea I was running out of video memory before. LFS (and other games like Crysis) ran just fine regardless. Running out of video memory used to mean performance took a nosedive (or everything just failed altogether), but now everything still remains quite playable.

Yay, progress.

Glad to hear you got it sorted out mate! Your lucky, you have PCI-e, i have gAyGP!