I'm sure you guys know this already but here's a couple of tips for helping with performance issues on a large grid and it doesn't hurt to go over them again....

The biggest performance hit in rfactor is the shadows, if you have them set to full then dropping to high will make a massive difference. The times i have struggled with a full grid, dropping this literally doubled my framerate. best of all - the only thing you lose are the in-car shadows (and possibly from the barriers) but you don't even notice the difference after a few mins.

Doing this i was able to run 32 cars with every other setting maxed out and it was smooth as silk, even at the start. I got the odd stutter passing the pits at Zandy but nothing serious - not sure why this happens here, it's not about frame rate, just seems to jerk a bit for some reason.

Of course if you have already turned down shadows then it probably won't help and setting it anywhere below high makes the game look very odd.

Track detail is also worth looking at - many tracks have a lot of 'hidden' objects which you barely ever see but are still rendered. Turning the track detail down a notch can stop this happening and will increase performance quite a bit. Visually, often you won't even be able to notice the difference.

If you use it, Another thing to check are your AA settings (Anti Aliasing, NOT Alcoholics Anonymous!) Even on modern hardware AA has a pretty big performance hit, if you are stuggling for frame rates then turning it down a notch can help a lot. I've also noticed the in game AA (ie. set through the config app) has much less of a perfomance hit than hardware AA (set through the GFX drivers). So if you have AA 'forced on' through the drivers then change this to let the app have priority and use the rF confing to set AA instead.

No. of visible cars: This has quite a performance hit (especially on DTM where the models seem to be very FPS hungry) however, if you set it to low then you get cars 'popping' in and out of view wich is very distracting. I normally lower the shadows first, then the track detail and then adjust the number of visible cars to as many as i can get away with. A minimum of 10 seems to be a good starting point.

Testing offline is a good performance indicator of what will happen online so start a weekend with 32 opponents and test your performance hit at the start of a race with all 32 cars on the grid and you at the back.

The race start and the first lap is the most stressful for the hardware so you should alter your settings until it's acceptable. It doesn't need to be perfect as things will ease a LOT after the first lap but in needs to be smooth enough that you can get away safely.

You can display your frame race by pressing CTRL+F. Ideally you need to be running above 60+ FPS for most of the race but you can get away with a drop to 50ish at the startline and odd occasions.

On the whole ISI sims are much happier on ATI cards, however some of the more recent drivers (in fact anything since the 10.4's) have caused issues for me - from missing car models to disco's and ALT-Tab lockups. It may not help you but definately something to investigate.

Now i know many of you run rfdynhud without any issues but i've also experienced stutters, runtime errors and lockups when using this. Probably doesn't happen to everyone but worth mentioning.

They are the main things i can think of at the moment. Hopefully you guys can come up with some more

Before races at night it is highly recommendable to optimise the headlights. Here is the link Doug has stored for that occasion:

http://www.race2play.com/homepage/show_posts/2297

I've tested your suggestions and other graphics options high and low to no avail. Too many cars on Zandvoort makes my computer go haywire (my specs are in my sig).

One thing that kinda bugs me is that rFactor only uses one core of my quad core processor. I tried that +fullproc parameter in my shortcut but it just makes things choppier (although it seems to use more cores?).

Maybe A1-Ring will be better when I get around to it.

Mhmm that a little bit strange, Dirt_Driver. I have a 8000 Quad 2 Core (2,33 GHz), a Radeon HD 4770, 4GB Ram, onboard Soundcard, Win7 64bit. My hardware are weaker, but i have no problems and i dont use +fullproc. My graphic settings are middle till high, have you try to put the visible cars down to 10?

I'm stumped... I've been doing short runs at the A1 ring until today, no more then 3 laps while trying to make a better set up to learn the cars around the track... Today I tried out Papa Ks and Chunx set up but I can't comment on either because I spent most of my time turning down the graphics while the track was extremely jumpy... I put everything to low, turned the shadows off, and went to trliniear instead of using anti-aliasing, and only had 6 cars visable on track.. everything I did only seem to make things worse... I also tried turning off rfdynhud, and that didn't change it either...

What is really weird is that I had a very good run at Zandvoort with the graphics...

I tried the McLaren F1 mod, 98 BTCC and V8factor afterwards and had no dramas even with the graphics at full, anti-aliasing x2 and 13 cars visable...

I then tried out Brands, Ricard and norisring to see if for some reason it was the carset... And had no problems at all...

I'm running XP, 8 GB DDR3 ram, AMD phenomenon II quad core, with a Nvidia Geforce 440 1GB graphics card...

I know my Graphics card sucks, because Nvidia don't support it anymore, and I can't get a upgraded driver for it... But it has been more reliable then my old one...

Pumbaa, you really shouldn't be getting performance related problems with that hardware. What are your frame rates in game? if turning down the settings didn't help then there's something else going on.

Funny thing is that the A1 ring is smoother than Zandy for me...

It's very odd... Like I said it was fine at Zanvoory, Brands, Ricard and the Norisring...

just did 3 laps, the first 2 it worked the best it has all day at 60-63 FPS, then as I approached the final corner it started dropping and got jumpy, it went down to 51 while I was cornering, and then 27 down the straight... then accelerating out of the 4th corner it dropped to 21... It wasn't consistently at those frame rates, it jumped all over the place... I've tried reinstalling the track but that did nothing...

Maybe it's the way the track is constructed? I've had similar issues in the past and if it's not going by the pits (cars popping in and out), then it could be something being rendered. I used to have fits with one of the older versions of LeMans in the middle of the Mulsane straight. It is puzzling...

To add to the oddness of it... I had very little trouble in the online practice races, so I tried a race skipping the practice and qual and had very little trouble except when heading into the hairpin... But when I tried a practice session afterwards and it would go crazy after a lap or so again...

Strange indeed. I've just wasted a second night trying to get rid of my "stutters" with DTM to no avail ... my framerate is good but I get this nagging stutter effect (?).

There's no way I'm going to lower my visible cars to 10 for a sim going on 5 or 6 years old!

To tell you the truth I had all display settings maxed out and 16xQ Antialiasing and 16x Anistropic filtering set since I've been running rFactor and thru the VHR, ILMS and F1 series with zero problems at all!!!

I'm fuming right now because I just tried other car sets on Zandvoort with 60+ visible cars and it runs smooth with maxed out display settings compared to the DTM mod which slows to a slide show at any crappy display setting at the first hairpin with 32 cars.

I'm giving up on DTM ... it has wasted too much of my time.

I envy you guys that have it running silky smooth.