Hi everyone,

Can't say how many years I've spent messing around with racing sims (since Stunts and Indy 500 with adlib support)... can't say how many times a new sim title triggered upgrades to my PC... thanks God I haven't tracked how much money I spent so far... countless fights with family due to new driving wheels and pedals purchases...

Also, I'm always trying to catch up with the racing sim community since the rec.autos.simulators times... but I've never posted a single message... This is the first time ever, I believe...

Anyway... to the point now... LFS represents my dreams come true... what a piece of software!... installation? just unzip the thing!... great physics, graphics, sound... fun.. and, of course... online!... great fun... use own and see others' skins... never thought something would beat GPL... this one did for me...

Now comes the "but": I'm yet to see a racing sim (or any other 3D PC game or title) with something that, to me, seems absolutely essential: constant FPS... In a racing sim, more than in any other type of game or title, FPS is not only essential, but crucial... everybody notices that even hotlaps improve with more frame rate… and what about when playing online...

Don't take me wrong... it would be a shame to take all the nice gfx stuff away just for the sake of FPS... I can't get tired of watching replays and enjoying how cool and realistic the environmental mapping looks on the cars... the shadows angles changing... the smoke and dirt... skid marks… countless polygons in each car... the tyres!... detailed tracks... and all that... ALL THAT… in something around 90 FPS with a readeon 9600... so cool!!...

But now, here I am… starting line of an online race with 15+ other guys like me, waiting for the green light... I'm 32 years old and the adrenaline is the same from the Atari 2600 times... and then... BIG FRUSTRATION of huge FPS decrease on turn one... exactly when you needed the most... and probably I'm not alone on this... others are also having FPS decreases... and the result is obvious on the virtual track right?... worse than going offroad when u know it would be easy to stay on, is to crash involuntarily… and get tons of “wtf” messages…

I don't know if I'll get any comment to this post.... but I believe some folks will come to me and say... "On my PC FPS are rock solid"... or "try to reduce detail level"... ok... points taken already... *BUT* I wonder if there isn’t a better solution to this... To me, it is almost impossible to find a balanced setting that gives me constant FPS... Obviously it easier to achieve that in game consoles, for example (like xbox or what have you)... easier to predict and program on a standard platform... I believe it’s hard in ever evolving PCs…

GPL is a piece of software from 1998... and just now, 2005, I was able to have a PC to deal with it, in my opinion, properly... i.e., 36 FPS in ANY situation...

...sry for this big post... it's basically a frustration that I have... and I'm not contributing with ideas... probably they would not work anyway (like having an FPS minimum threshold... I don't know)... but it would be great to see what others think, and if, in any way, we can also try to have the devs (by the way, what a great job u guys are doing!) from keeping that always in mind... I appreciate that LFS can run in low specs PCs, what makes me believe that they care... perhaps some of you with more technical expertise could make suggestions on how to better deal with this going forward... specially after spending some time looking at the suggestions posted so far .

Thanks everybody!
Mauro

1 thing that's helped me over inconsistent FPS is the FPS limiting feature. I have my GF FX 5200 limited to a maximum of 62 FPS and the result? When driving anywhere except the very start of the race where I see everyone, I get a consistent - permanent - FPS of 60 and get no weird effects that usually characterise the FPS jumping about

^ What he said. Limiting FPS or turning on AA/AF can help keeping the FPS at a lower but more constant rate.

The problem you speak of, namely lowish fps at a race start (or generally when many racers are around) is NOT, and I repeat, is NOT a problem of your graphics card. The problem is that when 15 racers are around, you have to calculate the very detailed physics x15. It's even pretty optimized as you run a lower detailed version of the physics for the other cars when online anyways, but even then it makes seemingly high-end systems cry.

Now, I don't know what CPU you have, but generally you can say for a sufficiently fluent play in many-car situations, about 2.5+ GHz CPU is needed. Also, AMD > Intel. This is true in games and especially in LFS - atleast that's my experience with CPUs.

Very nice first post for you MauroDiaz. Looking forward to seeing you around here more often.

Ahem, as for your question, limiting the frame rate can help as said earlier if you havent tried.

AA on an FX5200, wouldnt recommend that to be honest as it will lower your rates a lot. I have also found that turning on vsync caused more freezing in the game. If you want a lower frame rate, try turning on AF, its not as intensive as AA, and will improve the looks of the game at the same time.

Oh yeah for the record, I get those FPS with everything turned down or off that affects the FPS in both the GPU drivers as well as LFS..

Couple of tips:
-Make sure you use hardware shading
-Disable AA & AF altogether
-Use the dynamic LOD feature
-You may want to turn off the dynamic shadows completely
-Use the Max FPS limiter, drive online (FPS limiter off) with a few ppl and record the lowest FPS while it's still fast. Use that for the Max value
-Something else I noticed is that high detail flags killed my FPS, use simple flags all around

Quote from NotAnIllusion :

-Disable AA & AF altogether

I always run with these and turn all the other settings as low as they have to go, I don't need to see random special effects anymore than I need all the lines pixelated. LFS doesn't include much crap and I run it near full detail, I cannot run the GTL demo in night on my PC (about 5 fps) due to all the dynamic this and that (My PC is P4 2.8 ghz, ATI Raedon 9000, 512 mb ram)

After a quick test with my FX5200 128MB 8xAGP & Athlon XP 2500+ & 512MB Dual-DDR, all LFS GFX settings minimal, I found that (from 62 FPS, limited)
1) 2xAA & 2xAF reduce the FPS by 10 but is still smooth
2) Increasing AF from then on reduced the FPS to 25-32 and was unplayable
3) Increasing the AA was even worse

Conclusion
2xAA, 2xAF is the max I can do with this card while retaining playability so they do affect the FPS (adversely).

Well I run everything pretty much ma.... Oh, sorry!

To the point: I find that playing with minimum sleep can help on a single core cpu. Finding the balance between background tasks and LFS. What it should be depends on your system.

On a multicore system, limiting frames is an option I find appealing, but I have never ben able to get that particular setting to work as expected. In rFactor I have limited my fps to 40 and it never ever drop below. That's awesome, and I'd like the same for LFS. If I set the limiter to 40 fps, I get a very 'jerky' game, where framerate is anything but smooth. Even though my system is capable of putting out 100+ fps most of the time, and very seldom drop into the 60s, locking at 40 let me see anything from 20 to 80fps, but with sudden changes in framerate, which is even worse than low fps.

I have experimented a bit, trying to find the bottleneck, and it's definetly CPU and/or RAM. Crancking gfx settings as high as they would go and even using two screens hadly dent the fps*, but put a few AI in the mix, and even the most high-end system is brought to it's knees. No wonder most developers fudge the AI....

One can only hope I get the fps limiter working someday, as a stable framerate is preferred over high framerate any day (as long as the stable fps is acceptable, of course. No good having stable 25fps.)

*
Amd Athlon 64X2 4200+ @ 2675
Abit KN8
XFX 7800GTX
1Gb twinMOS PC3200
3200x1200, 8AA, 16AF, high quality in drivers, all maxed ingame. Online 70+fps.
800x600, 0AA, 0AF, normal quality in drivers, all but HVS turned off, back of the grid, 12 AI, 25fps going into turn 1 on Blackwood.

Hmm why did you put the FPS limit at 40? That's a huge waste if you ask me. You said your system most of the time cranks over 100 FPS, so use that value for the limiter.

Quote from NotAnIllusion :

Hmm why did you put the FPS limit at 40? That's a huge waste if you ask me. You said your system most of the time cranks over 100 FPS, so use that value for the limiter.

If you limit your framerate a bit above your minimum frame rate you will not have huge spikes in your frame rate so you will drive better. I limit to 40 on my laptop and this then gives me a solid 40fps no matter the situation.

If you read my earlier posts you'll gather I'm aware of that My point is it's clearly not working properly for atledreier. I might be because he's simply got a too quick system, so upping the limiter value might prove better than using a limit of 20 FPS less than what I use with specs a couple of times better than mine

Quote from MauroDiaz :

(or any other 3D PC game or title)

Doom 3

Enabling vertical sync in-game and triple buffering from the video card's settings and then setting a frame limit to under the screen's refresh rate (60Hz in my case since it's a TFT) helped enormously at keeping a constant framerate during all parts of a race.

Quote from NotAnIllusion :

2) Increasing AF from then on reduced the FPS to 25-32 and was unplayable

Constant 30 FPS is good enough.

We must have a very different idea of what's "good enough".. IMO The difference between 60 and 30 FPS is noticeable, and it unsettles my driving rhythm driving at the lower value. Whatever floats your boat.. mine just about stays afloat at 60 FPS

It really depends on the perception on the user, and for some people 30 fps will surely be ok. For me, 30 fps is also "ok"... but not good by any means. I can very well notice the difference between 30 and 60 fps, and at the former my driving will suffer considerably.

Also, to all here, please don't start digging out the "humans can only see 25fps" myth. It's outdated, it's misinterpreted, not true and I'm sick of hearing it

You are talking here about constant FPS. Why? Yes, 20 FPS on start isn't nice and one "well aimed" framedrop can destroy you all the race. But I see no reason why to limit FPS. OK, constant FPS is better than 10 - 60 FPS, but if the game runs 120FPS and faster, how it will hurt the gameplay?
All right, someone can think "lower max FPS = higher min FPS" but that is nonsence. Does anyone know how can lower max FPS force min FPS to be higher?????

IMO some optimalization of the code is needed, especially I wish to know if LFS supports any SIMD instruction sets(I mentioned it more times but I've never ger an answer). SSE and SSE2 can help to accelerate physics calculations, for example, MMX can accelerate graphics a little. That's the way to higher FPS.... not an limiting

There is definatley an advantage at running 60 rather than 30, but I don't feel it's worth the loss of AA, I can't read the road at all without it. I don't know what FPS I get, but I think it's about 45 FPS.

I also use a large resolution - 1280 x 960 I find this better with less details as it allows for more visible objects in the distance.

@MadCat:
Nah, the idea behind limiting the fps is to minimize the jumping of the fps. A steady 50 fps is better than the fps jumping between 60 and 120, because you will notice the difference, even if its only subconscious.

Quote from AndroidXP :

@MadCat:
Nah, the idea behind limiting the fps is to minimize the jumping of the fps. A steady 50 fps is better than the fps jumping between 60 and 120, because you will notice the difference, even if its only subconscious.

Exactly. That's why I use a value of 40. It's fast enough for me, and all that waiting allow my system to breathe easier. I know my system can pump out more fps, but I really don't see the point. I'm not faster, but constant fps is easier on my eyes, so I use it.

Apparently something has happened to the limiter thingy, cause it's working like a charm now. I might try upping it to 60 and see what happens. And the v-sync/triplebuffer thing sounds interesting. But isn't it necessarily a multiple of your screen res, then? So if I'm running 85Hz refresh, I get either 85, 42.5, 28 ... ? Cause if my system can't get a frame done in time, it will have to wait a whole scan cycle before it's allowed to draw the frame? Is that where triple buffering comes in? What does triple buffering do, anyway? I know double buffering, but triple seems redundant to me. I'll go and do some tests now.

yep. its REALLY is the changes in frame rate you notice more than the actual framerate itself.

Noone is saying that 60 is not better, smoother and more fluid than 30 BUT steady 30 is FAR better than a rate that bounces between 30 and 60 all the time as this will effect your speeds far more.

I tried setting v-sync on, and turning the limiting off. I have set screen refresh to 75Hz, and it pretty much stay there. Looks smoother at steady 75fps than when I let it run unlimited at 100+. Online I have no fps issues, so I'm leaving it at v-synced, unlimited fps for now.

Glad you got it sorted

OK, now I understand. Well, for me aren't framerate jumps problems... and it's good to see FPS @ 120 and higher Hehe....
But 30 FPS I find quite low... I think that 50 could be better. LFS recalculates physics every 1/100 sec, so idea FPS 'd be constant 100 (I dream about it @ night)