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Cpu and GPU not fully used but framerate decrease

Discussion in 'ACC Hardware Discussions' started by kregs77, Dec 10, 2020.

  1. kregs77

    kregs77 Rookie

    Hi,

    I've an old configuration, intel I7 4770 and Geforce GTX 1060 , 16 GB of RAM, the game works fine in low settings. i've capped the FPS to 90 fps. But at start of race with full grid , i've a FPS fall at 70 or 75 fps and came back at 90 fps when i'm in race with few cars. Normally you said. But i want to add more cars visible (10) to prevent suprise at first turn... I've install msi afterburner and suprise my GPU and CPU are not fully used, they are also between 60 and 70 % each one. if i increase graphical settings, fps decrease and not more GPU CPU using... Anyone has an idea why my material are not fully used ? Thank you for your help !!
     

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  3. AndyK70

    AndyK70 Alien

    You are viewing the overall cpu load, not the single core loads.
    ACC uses a main thread for all the main parts and organization of the sub threads (physic, AI, etc.) which utilizes only one core.
    So ACC is heavily dependent on single core performance.
    Your 4770 is a very old (at least 7 years) one and can't perform as good as the modern ones. One other user wasn't accepting my statement, that his 9900K @5GHz is the limiting factor and called it BS. Now he has a Ryzen 5600x and he says it is a game changer more than the 3080 he got previously.
     
  4. kregs77

    kregs77 Rookie

    Thank you for your reply, i will check if one core is at 100%, but it seems to me logical that's the bottleneck :)
    i'm waiting the end of penury for upgrade to new config with Ryzen 5 3600 which seems to be the best quality price actually
     
  5. Micii1

    Micii1 Racer

    I am 2 using a 9900k at 5.0 all cores an vr only. Gpu uses about 60% wit medium to high settings frametimes about 7-9 at normal. But if it goes to 11-12 got a lot of stuttering. Can that be the cpu?? I have a 3080 and 32 ddr4 at 4000mhz
     
  6. AndyK70

    AndyK70 Alien

    @Micii1 I'd say so. When the GPU is not at 99% and you're getting fps drops the CPU can't feed data fast enough.

     
    seb 6th gear likes this.
  7. Yeah with the 5600x I can confirm that ACC is fully GPU limited once more and gets to 100% gpu usage. I can do 120-140 fps 4k at high settings in 2d (and around 100-110 on Epic). Crazy good performance.
     
    Micii1, its.me and AndyK70 like this.
  8. Micii1

    Micii1 Racer

    Still would like to see if it really works better for vr with the 5000 serie..
     
  9. Oh it does by a mile. 90fps is definitely possible with it (depending on quality settings). With my quest 2 it runs 90fps with a few dips with very decent visual settings.
     
  10. F1Aussie

    F1Aussie Racer

    How do you get so much FPS? I have a 5950x and rtx 3090 and get no where near that.
     
  11. bbman

    bbman Racer

    Caveat first: I'm on Zen2 and Turing, so I can't speak from personal experience. That said, I'm not sure I'd be comfortable advising someone with a 9900k to change his whole system so he can enjoy what should be a 15-20% increase in performance (at best probably, since those numbers are from synthetic benchmarks). Micii indicated his fps are usually in the 120-140 fps range, dipping to 83-90 (so just below most HMD's refresh rates) which might be felt as annoying stutters. On the whole, that's still a better performance than pixelcowboy describes in the quote, although Micii never told us the resolution he runs to really make a valid comparison from the outside.

    I've seen benchmarks on these forums (very old ones) that indicated ACC basically stops scaling at 4 cores. If this still holds true, the performance with higher threadcount CPUs will always be off - making anything other than a 5600x or 10600k just for ACC a worse choice in terms of price/performance...
     
  12. AndyK70

    AndyK70 Alien

    Going to a 5600x is not about more cores/threads but way higher single core performance. This feeds into your argument of ACC stopping to scale at 4 cores...
     
  13. bbman

    bbman Racer

    Which is why I quoted single-core benchmarks - 5600X gets smoked by 9900k on all core workloads due to its 2C/4T-advantage... ;)

    My argument is: if ACC stops at four cores, the biggest limitation is the engine itself as it kneecaps pretty much every modern CPU. I know a program can only part out calculations to so much threads until the overhead to sync it all kills all the gains from going one more, but to suggest a 9900k is the root of stuttering is only true if you view it solely within ACC's restrictions - and I would argue an estimated 10-20 fps gain won't really make up for completely changing out ones system for most people...
     
    esox71 likes this.
  14. AndyK70

    AndyK70 Alien

    Sorry, I can't see any quote/references/links to specific benchmarks in your posts of this thread. Could you provide some?
    Any review I saw on tech sites like computerbase.de
    pcworld.com:
    anandtech.com

    Errr...? o_O
    We are talking specifically about ACC having stutters...
     
  15. bbman

    bbman Racer

    You're really doubting a CPU with 2 more cores has an inherent advantage when a program uses all of them? o_O Fine, just from the first page of google, quoting mostly cinebench (AMD's stronghold to boot):
    https://www.cpu-monkey.com/de/compare_cpu-amd_ryzen_5_5600x-1750-vs-intel_core_i9_9900k-890
    http://hwbench.com/cpus/amd-ryzen-5-5600x-vs-intel-core-i9-9900k
    https://nanoreview.net/en/cpu-compare/intel-core-i9-9900k-vs-amd-ryzen-5-5600x
    It's a problem with reviews in general - for (testing) time's sake, last gen products mostly fall by the wayside. But I'm sure you'll find similar data comparing articles on your beloved reviewing sites - if they quote hard numbers...

    Can we now bury this "5600X is the second coming of christ"-type argumentation? Yes it's a beast, but so was the 9900k merely two years ago - and it's still a damn fast CPU today, only surpassed by its successor and (more or less) the new Zen3 processors. Changing from a 9900K to a 5600X will probably push you over the edge into smooth gameplay if you're already on the cusp and the program is as restrictive as ACC, you will also see losses where all-core computing is needed. If one is about to invest € 450+, there better be some more measured arguments than the hypetrain "doo eet!!!"...
     
  16. AndyK70

    AndyK70 Alien

    sorry, I'm a bit confused by your argumentation.

    he asked:
    I answered I'd say so and quoted a post from another person who switched to a 5600x stating the big improvements he had in ACC since then.

    You argued
    I never suggested to go specifically to a 5600x. I am stating that a 5600x in ACC is doing better than a 9900K @5GHz on all cores by referencing a user who has done the switch.
    In the second part of this quote, as I understand it, you are arguing against a 5600x because that gain is mainly from synthetic benchmarks.
    Well, I quoted a user who has done this and not a synthetic benchmark. I quoted online media reviews which did not use solely synthetic benchmarks but also real app and gaming performance.

    And now you argue
    What the freak are you talking about? (edit: presenting comparisons done via synthetic benchmarks... o_O)
    We went from performance in ACC with an 5600x as an example of the new Zen3 lineup instead of an 9900K to "mainly only in synthetic benchmarks" to "you sure when using all cores?" ... :rolleyes:

    I don't know what he uses his pc for and even if he wants to change at all!
    I did not suggest him to switch his 9900K to a 5600x.
    He asked if it can be the cause of his observed issue in ACC(!!) and I said I would say so. That's all! I don't know what you are making a fuzz about?!

    If he wants to change his system... if only gaming than a 5600x should be enough, if he needs the PC to to video editing/rendering and other demanding stuff then of course he should go for a higher core count, i.e. a 5900x or 5950x if he can afford it...
    Are we now done?
     
  17. kregs77

    kregs77 Rookie

    Thank you for your help , i've upgraded my motherboard and CPU to a Ryzen 5 3600 and now my GPU works fine at 100% , i've increase details and FPS are stable at 90fps (i'm using FPS locking) !!
     
    seb 6th gear and AndyK70 like this.
  18. Vel

    Vel Simracer

    If i run 1080p Imola, 30 car grid. ... I wind up at a consistent 60-70 fps with most settings at High. Driving is consistent and reliable. Smooth. Yes, it's nice to see 100 +fps or similar when practicing alone on track but i've never felt the need for greater than 60-70 fps. Nor can i report issues with input latency, screen tearing, stutter etc.

    I'm a bit surprised. Are you trying to run this on 1 monitor, or a High refresh rate 'gaming' 144hz monitor?
     
  19. its.me

    its.me Racer

    Basically I fully agree, but I think it is not always the case. You can see my specs in the signature. I also have frame rate drops (from 60FPS down to 52FPS) for several consecutive seconds at the start of some races (e.g. Imola with 30 cars). GPU and CPU loads are below 100%. I also have used the Windows performance monitor to record the load of all cores. There is one core loaded most, but its load is max. 73% during the frame rate drops. GPU load is around 96-98%. GPU-Z showed that my GPU was Vrel limited - maybe this is the limiting factor in my case? I don't think it is CPU limited.
     
  20. seb 6th gear

    seb 6th gear Racer

    ACC is heavily single core performance on main thread. This is a CPU bound scenario.
    In a heavy CPU bound scenario RAM speed and latency is critical, every gain on the RAM translates immediately into better performance.
    So in the case of kregs77 the DDR3 was holding his system back. I've been there before upgrading to Ryzen a couple of years ago (I used to have a 4790k with 1800 c9) and it didn't cut it especially in VR.

    People are arguing a lot on "ACC is GPU bound". I can't disagree with enough strength to that kind of statements.

    I've been using my 1080 ti with 2700X, 3700X and now 5800X, at all time I've used Ryzen timing calculator from 1usmus to optimize my RAM kit from 3200c14 to 3666c14

    upload_2020-12-25_17-45-40.png

    Last week I've upgraded only my CPU, the rest of the system remained the same, same mobo, same RAM kit, same GPU, same 460.79 drivers, and I've used the same replay file to capture 3 min and the difference is mind blowing.

    upload_2020-12-25_17-37-50.png

    I don't have figures for previous CPUs, but there wasn't ever a leap like this.

    the pacing consistency is improved a lot too
    upload_2020-12-25_17-41-9.png

    There is one major difference though between the two runs showed here, on the 5800x I now have GPU Hardware scheduling activated now. I wasn't using it on 3700x as the last time I visited that option I had some UE4 crashes in its early implementation when feature was released in Windows 10. Now with NVidia 460.79 drivers and latest Windows patch it works flawlessly, it improves mainly the 0.1% and 1% lows. And again, that features off loads a part of the CPU rendering pipeline work to the GPU, so it reduces the CPU bound.

    Regarding the CPU multi core scaling this thread is interesting
    https://www.assettocorsa.net/forum/...unt-and-ram-scaling-in-acc-ac1-and-r3e.59867/

    But if it quickly shows scaling stops at 4 cores, you must remind that every test ran from a replay isn't as CPU intensive as live driving against AI e.g. as physics threads are stopped (quote from Lord Kunos himself https://www.assettocorsa.net/forum/...caling-in-acc-ac1-and-r3e.59867/#post-1084562 )

    So without falling in the "more is better" meme, you need to consider are you using intensive apps on the side ? Are you a VR user ? and chose your CPU accordingly. 6c12t look like a minimum nowadays, although your favorite sim won't eat all, just remind Windows may do a couple of things in the background.

    But, yes, ACC is CPU bound, even more so in VR.
     
    AndyK70 likes this.
  21. its.me

    its.me Racer

    But none of the single cores of my CPU is fully loaded. So CPU limit can't be the reason. Maybe DRAM speed is a possibility. I run DDR4 3200 with XMPII.
     
    esox71 likes this.

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