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Assetto Corsa: Cars are slower in multiplayer.

Discussion in 'Assetto Corsa' started by Paul Borg, May 31, 2014.

  1. Firstly hello to all, I am new to Race Department.

    This is a problem I have experienced with other games on consoles as well. I am reasonably new to PC and haven't done much online, but I did play a little bit of Race 07 online and never experienced this problem (refer to title).

    But this did happen to me in a big way on Xbox 360 with Race Pro, and the more cars in the lobby the worse it was. I believe it has everything to do with my crappy internet connection, which is 7.03 mbps download, and 0.32 mbps upload. Yes you saw correctly 0.32 upload, and that is measured on speedtest.net and at best. Also I live in Sydney Australia, but not that that should matter. This is the fastest connection I have available to my house, so I am pretty much screwed in that department.

    I will give you an example of what I mean by cars are slower in multiplayer. I have clocked up nearly 600 hours on AC, and consider myself to be a pretty decent driver. I run a 10 lap multiplayer race on Vallelunga with the McLaren GT3, and can only once (pushing very hard and clean) manage a 1:33.8xx. Every other lap was 1:34.xxx and they were clean and fast. Yet when I hotlap with same car and exact same settings, I consistently run 1:33.5xx or around that. And pushing hard can manage a 1:32.9xx.

    My question is, has anybody else experienced this? I googled it and came up with zilch.

    I am very frustrated and have tested this out now with different cars and track combos and still the same. Like I said, I believe it's my shitty internet so unless someone else has a similar internet speed to me, I doubt you will notice this, but I have no way of playing AC anywhere else to test my theory.

    Cheers guys.
    Last edited: May 31, 2014
  2. Ross Balfour

    Ross Balfour
    #99 | Roaring Pipes Maniacs

    This could be due to in hotlap conditions, you can set an air temperature that's optimal, while online - the track or air conditions may be worse, and laptimes won't be as good.

    It's nothing to do with your internet you'll be glad to here, it's the same for everybody. I can consistently run 56's in a Mclaren GT3 at Nurburgring in hotlap conditions, but in an online server I can only run 57's, even with what feels like a great lap.

    I'm only guessing, but the fact that it is the same for everyone, means that it's not an issue at your end!
    • Agree Agree x 1
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  3. I can say i am even faster on some combos than offline.
    It depends on how i feel when i get pushed from the back :p
    • Agree Agree x 1
  4. Frank

    Administrator Staff Premium

    Apart from what the other guys say, your connection might actually have some effect. Your ping will most likely be trough the roof and the server will have to re calculate your position constantly, people behind you will see the best effect from that. I can see why the times will be off like that as it is not your client telling the server your time, but you actually complete the lap server side. If you can follow that.
    • Agree Agree x 2
  5. The position is not calculated on the server side. I am pretty sure that all physical simulations are run on local (either in hot lap or in multiplayer) and is your local computer that reports the position to the server*, and this distributes it to the other players.

    otherwise you would have a huge lag between user input and car reaction that would make online undrivable unless you had a ping under <20 ms or so.

    To OP, the only reason I can think is differences in track temperature (as pointed before). I don't know how to monitor track temperature online, but you can keep an eye on your tyre temps and see if there is any difference between online and offline.

    * The server is quite likely to estimate "intermediate" positions given your last position, velocity and acceleration to try to remove some "shaking" between position reports form your computer, specially on high pings, but you will not see any of that as these positions are reported to the other players and not to you.
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  6. Frank

    Administrator Staff Premium

    I am sure you know more about it then me, I am just basing it on the tech I am familiar with from other types of games.
  7. I am not sure if I know more than you or not, but what is for sure is that both of us together know more than each one separately ;)
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  8. I've been testing this for some time now, and I'm 99% sure that the ping and/or upload has everything to do with this. And this is not something I am making up, or mistaken about. My connection is terrible, and I have seen the differences of my lap times online. And it varies depending on the server, internet traffic in my local area, how many people in the lobby and so on.

    I know it's got nothing to do with framerate, cause I always run with Vsync on, no matter if I'm on or offline. My framerate never drops below 59.9 ( I use MSI ), and there is plenty of room left for the GPU usage.

    I am a consistent driver, yet in some rooms I can hit a 1:45.xxx on Mugello with the McLaren GT3 on medium tyres, and other rooms I can only manage a 1:47.1xx. I don't think the air temperature can make that big a difference, but I will test that. I have the air temp set to 26 degrees celsius, honestly not sure what the optimum is. But with it set like that can run 1:45.6xx against the ai on medium tyres and same settings on the car of course.

    My point is my connection is so bad, and this sort of thing has happened to me with other games, as I mentioned in my original post. It never happened on Forza 2, and my connection was even worse then. But on that game the lag was so bad, the cars would fly in the air and do all sorts of crazy stuff. So I would guess it has something to do with the netcode, but I'm no expert. I can only report on what I experience, and I have a LOT of experience when it comes to online and offline racing.
  9. When setting up a server, one has to adjust these 2 parameters:


    Without knowing these, and without being sure if they are identical online and offline, I don't think we can conclude that ping does or does not affect lap times.

    Does anybody know how to check road and air temp on a server when racing?
  10. I just tested it by dropping the air temp to 10 degrees celsius ( which is as low as it goes ), and was doing 1:46.1xx ( only did three laps ). Air really doesn't make much difference. I think I could have hit 1:45.8xx.
  11. Shouldn't be road temp the one that has an effect on grip?
  12. Please tell me where it is that you can change Road Temp? In the game you can only alter Ambient Temp. I do not know how to create a server online, but I would be guessing you cannot change Road Temp online.
  13. Chris

    Ted Kravitz Appreciation Society Staff Premium

    You cannot change the surface temp of the tarmac. Only ambient temp and time of day.
    • Agree Agree x 1
  14. I realise this, that is why I posted that. ;)
  15. I never configured a server myself, so I don't really know. However I vaguely remember people complaining of too short qualifications as they didn't have time enough to adapt their set ups to the different possible track temperatures.

    In a quick search on the official forums seems that there is a file called /server/cfg/server_cfg.ini where you can configure all the server parameters (http://www.assettocorsa.net/forum/i...use-the-server-last-updated-23-may-2014.9376/), in another example I found someone had:



    I also believe that offline events have similar configuration files, however I do not have access to AC right now and I can not check. Maybe there one can change the surface temperature?

    I also have no clue on how track temperature varies along time given an initial air temperature and time of the day, but I would suspect these parameters might also play a role. Even sun angle might have an impact (as it does in real life)

    More problematic is that I do not know how to infer surface temperature once in game, as initial temperatures we see in pits are probably air temperature and not surface.

    Maybe someone who runs and configures a server can enlighten us?
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  16. I'm sure if someone was smart enough, and really wanted to do it, they could change the .cfg files. But to me that would be like cheating, I am talking about what can and cannot be done in game. And as stated before, you CANNOT change the road/track temperature ingame.
  17. I have had my own car lag-warp though when my connection was particularly bad. I don't think it's sending your every command to the server before letting you take action (like some MMOs do) but it does seem to synchronize the players periodically. I haven't played online enough to get consistent lap times and tell if it changed things compared to single player so I don't know if it has an effect. And I'm not tracking what version things happen on so who knows maybe they were just trying something.
  18. Tire ear and fuel settings online vs offline?
  19. I haven't noticed any difference offline and online. I'm pretty sure I've gone faster online as well as slower.
    • Agree Agree x 1