Car dependant performace issues

Discussion in 'Technical & Support' started by AlenC, Aug 4, 2018.

  1. AlenC

    AlenC Registered

    Joined:
    Aug 2, 2018
    Messages:
    36
    Likes Received:
    15
    Hi, I recently bought RF2 and I really enjoy it, but I'm having problems with occasional low fps.

    My specs are:
    win7, FX6300, r9 270, 16GB RAM

    I have the graphics settings set rather low and on an empty track I get 60-80 fps (if I set everything to minimum I get 120-140fps). However, when there are other vehicles on track, my performance suffers , in my opinion, disproportionally (even with minimal settings). Two newest cars are especially impactful: March 761 (fps drops to 35 on race start) and Brabham BT44B (45fps). For comparison, with Brabham BT20 I have 55fps on race start, which I find acceptable.

    I did all tests on Zandvoort with clear weather and 10th place on grid.

    Is this behavior normal? Cars I used in testing don't look much different to me, I feel like they ought to perform similarly. I also find it difficult to accept that few extra models make that much of a difference. My CPU is barely tasked; one core gets 50% load and rest are around 20%. So whatever happens, bottleneck must be on GPU side.

    Is there something I could try to improve the performance? I'd like to try paid content, but I'm concerned I won't be able to use it.

    I'd also like to know what is target hardware to be able to max out settings in RF2? My GPU is only slightly slower than recommended on steam store page, which is probably outdated...

    Thanks for any help!
     
  2. Lazza

    Lazza Registered

    Joined:
    Oct 5, 2010
    Messages:
    12,346
    Likes Received:
    6,572
    When judging CPU performance press Ctrl-C while in the car. The graphs shown (horizontal bars) are a better indicator of CPU timing than task manager CPU loading. Also when you press Ctrl-F to show the framerate the game will show you the CPU and GPU timings and put a * next to the one that's most limiting the game.

    Given your hardware I'd guess what you're experiencing is about normal. Your CPU is 6 years old and your GPU is a 5 year old repackage of a 6-7 year old GPU. You can't easily judge the 'load' of cars by eye; the textures muddy the details so you don't really see busier or simpler meshes, while different (new) shaders that are doing a little more and causing more load may not be obvious either.

    I don't know what you've got visible cars set to, try lowering that to help with grid FPS.
     
  3. AlenC

    AlenC Registered

    Joined:
    Aug 2, 2018
    Messages:
    36
    Likes Received:
    15
    Hi, thanks for the reply.
    I did monitor performance with in game meter (mine is for some reason ctrl+j) and it has shown same thing as task manager.

    I just did another test to compare two cases visually. You can see I have only 9 cars visible, so I don't even see first row. Visually I don't see where is that performance going. I tried ctrl+F option and I couldn't see * next to any value, but I noticed GPU usage is lower with March761 (lower framerate); 85-95 and occasinally 98, while with Brabham BT20 it stayed constantly on 99% GPU usage (screenshots are from beta branch, I tried it to see if there'll be any improvement, but the performance stayed the same). 20180804131749_1.jpg 20180804132006_1.jpg
    I know my computer is old, but so is rFactor 2. I knew this game doesn't run that well and is not as attractive visually as other sims, but driving feels great and that's all that matters. However I'd prefer not to have to change visual settings depending on car I choose to drive.
    I'd really like to buy Sebring and at least endurance pack (and more content that's coming in the future), but I'm worried if I'll be able to run it properly. Can anyone tell me if endurance pack causes such performance issues? Or even better, reproduce this case comparing March and Brabham. I find it difficult to accept this as a normal behavior...

    Thanks again!
     
  4. Lazza

    Lazza Registered

    Joined:
    Oct 5, 2010
    Messages:
    12,346
    Likes Received:
    6,572
    Your second screenshot shows what I would call the Ctrl-C graph. Ctrl-F (or whatever yours is) should show FPS. Can you try to capture that one?

    *Regarding the age of rF2, it was initially released as beta in 2012 and sort of 'released' in 2013, but it's undergone continual development and is known to be more demanding than other recent games. So don't expect 2013 hardware to run it well.

    @AlenC Sorry, I didn't read part of your first post properly - don't select anything from the 'BETAS' tab in steam. rF2 doesn't have actual betas, that section is only used to select older versions. It's confusing but the beta function was the easiest way for them to allow dropping back to older versions. So make sure to 'Opt-out' of all betas.
     
    Last edited: Aug 5, 2018
  5. AlenC

    AlenC Registered

    Joined:
    Aug 2, 2018
    Messages:
    36
    Likes Received:
    15
    Thanks for the heads up, I opted out of betas on steam!

    Here are new screenshots: 20180804210216_1.jpg 20180804210350_1.jpg

    I did some tests earlier and increased number of visible vehicles, which is interesting because the performance difference is even greater.
     
  6. stonec

    stonec Registered

    Joined:
    Jun 19, 2012
    Messages:
    3,399
    Likes Received:
    1,488
    Is that a 2 GB GPU? If so, my guess is that you are running out of VRAM, which would explain the dramatic drop in FPS. It would also explain the low GPU usage, because once you are out of VRAM, GPU has to retrieve information from RAM, which means your GPU sits idle waiting for the next frame.

    Newer cars and tracks are generally more VRAM heavy due to improved textures and models and once you reach the VRAM limit of the GPU, rF2 performance falls off the cliff. I calculated that each modern rF2 car takes roughly 50 MB VRAM on high opponent detail, so with 20 opponents, it's already 1 GB consumed. The track itself can easily take another 1.5 GB, plus any background windows like web browsers.
     
    Lazza likes this.
  7. Lazza

    Lazza Registered

    Joined:
    Oct 5, 2010
    Messages:
    12,346
    Likes Received:
    6,572
    Yep, probably what @stonec says. Graphics memory, plus possibly PCIe being used. Until fairly recently I had a slower CPU (to the point of causing some slow-motion in the game) but FPS on my 7970 wasn't bad at all - and I think that GPU is quite similar in raw specs to yours, but it has 3GB. Now that I've upgraded to a new CPU and PCIe 3.0 x 16, in the same scenario as your second one above I start on 62fps with dips down to around 50, but that's also with all settings on med-high and shadows on Max (they just happen to be my current settings, I wouldn't call them optimal). Same vid card as I had before.

    The BT20 starts at 89 and only dropped to 86, so definitely lighter, but with both mods my GPU time shown in the top left was 0.01xx, not your 0.07xx, so there's definitely some overhead happening there.
     
  8. AlenC

    AlenC Registered

    Joined:
    Aug 2, 2018
    Messages:
    36
    Likes Received:
    15
    Thanks guys, yeah it is VRAM. I should've checked it again. I did monitor it before, but usage was around 1400MB with full textures so I figured it's not an issue in rF2. Unfortunately, it seems difficult to lower VRAM usage for March 761, but once it dropped below 2GB fps went up to 60 (it seems something is capping my framerate to 60, probably AMD profile, even though I set it uncapped).

    Too bad, but it seems I'll have to pass on future rF2 content then. It's weird because I always thought VRAM limit is easiest to solve. Texture resolution can be lowered and models can have LOD's (are meshes stored in VRAM as well?).

    Anyway, thanks again for help. I'll do some more tests to see if I can find a setting that works...
     

Share This Page