Lower FPS on RX580 vs GTX970?

[djtopa]

I need a opinion of you guys.I have a LG 21:9 LG29UM68-P monitor so with ex GTX970 4GB Assetto worked fine on 2560x1080 almost every setting on very high-max(AA4x,Antistropic16x,FAAA,World very hight,PP hi,Reflection hi-static (I never drive with full grid always max 20 cars) etc...but I had a lot of monitor shutter I just hate.
So I bought RX580 Nitro+ 8GB so I can use 75hz Freesync.
I installed latest drivers (I have Win8.1 so I had to use Win7 64bit drivers)...run the Assetto on same track Ring with same 20 AI cars and graphic settings (See above) and FPS counter showed almost 10FPS lower then with 970GTX 4GB...and same shutter I hate .So I turn FPS lock to 73 and shuttering is almost gone game looks great and smooth but still I cant beleve lower FPS with double of VRAM.
Assassin Creed Origins and Far Cry 5 are working a lot better then on 970 GTX btw...
Any ideas?Thanks

my specs:
Win8.1 64bit,i5-4690K 3.50GHz,16GB Ram 1600,RX580 8GB,SSD,650W PS,21:9 LG29UM68-P
Logitech G27 wheel

 

[jlnprssnr]

Assetto Corsa is rarely VRAM limited, so having more than 4GB is pretty much irrelevant. Try monitoring your CPU utilization if you’re running into CPU limit. AMD Dx11 drivers require more COU load than Nvidia. It’s better on Windows 10 because of WDDM 2.0, maybe try upgrading

 

[jlnprssnr]

Also make sure to enable Freesync in the monitors menu, sounds like you don’t have it enabled yet if you still see stuttering at ~65 fps

 

[djtopa]

Sorry I forgot to write yes Freesync is on in the monitor menu also in windows monitor settings is on 75hz...I had shutter before FPS lock now I dont have...gonna try to monitor the cpu...

 

[RasmusP]

Sorry I forgot to write yes Freesync is on in the monitor menu also in windows monitor settings is on 75hz...I had shutter before FPS lock now I dont have...gonna try to monitor the cpu...

Don't monitor the CPU. You won't see the single thread limit. Your CPU will look totally fine while in reality the single thread limit is reached.
Monitor your graphics card instead. If the load isn't over 90% it's your CPU that's limiting.
Since you have freesync now: maybe limit the fps to 55 or something so this can be maintained all the time? You shouldn't see any stuttering with freesync above 50 fps!

Btw: with too many apps activated in ac my I7 2600k @4.4 GHz can't maintain 60 fps if too much is going on. Multiplayer race start with 24 drivers, racestart with more than 15 AI etc.
Also try to put the reflections to static. I think it's the rendering Frequency set to the lowest.
This should give you a better CPU performance!
Not sure if you already did this as you state "reflections hi-static" but I thought I'd mention it anyway.

 

[RasmusP]

Oh I forgot to ask: What CPU do you have?

 

[djtopa]

Intel i5 4690K 3.50GHz,16gb ram....btw reflections are on static....Noob question whats the best way to monitor gpu and cpu?

 

[RasmusP]

Intel i5 4690K 3.50GHz,16gb ram....btw reflections are on static....Noob question whats the best way to monitor gpu and cpu?

I use "openhardwaremonitor" when I also want to see fan speeds and voltages. It's free and only a standalone .exe-file. You can easily set it up to show the graphs and log things you want.
When also want to have an in-game overlay, the best fps limiter (in my opinion) and some nice features to tune your graphics card: "MSI Afterburner + Riva Tuner Statistics Server".

Important: Although all monitoring tools and the taskmanager will show you that your overall CPU-Load isn't higher than 30-60% and also no single core/thread is at its maximum: There is a hidding single-thread limit!
All monitoring tools show an "average" but important are the "spikes" (I don't know the real terms for this but I think you understand what I'm saying).
If you're interested in that you need "process explorer", right click on the program you wanna watch and go into it's properties -> threads and you'll see all threads of a program. They will mostly be things like render thread, physics thread, sound thread etc.
The limit here is 100% divided by the amount of threads your CPU has. 4 for your i5.
So 25% is the single thread maximum!

You'll see that the moment the main thread of Assetto Corsa comes near 25%, so probably above 22% as you won't see the spikes, you will experience FPS-Drops.

You have the k-version but not overclocked? I'd say your CPU may be the issue here... No need to buy something new. If you have decent cooling (log your CPU speed and the temperature with openhardwaremonitor!), you can easily overclock that CPU to 4.2 GHz!
Your CPU shouldn't go higher than 78°C though at any point.

At this speed, your problems should be gone

That was a lot of input I guess. Take your time and don't rush things. Do not overclock without reading some guides and understanding about what to do etc. and don't think you need to buy anything.

 

[djtopa]

Thanks for souch a long answer.Gonna look all that.Still cant beleve lower fps with new gpu (if cpu is "problem" how come with 970gtx I had more fps)but freesync is dope!so smooth

 

[RasmusP]

Thanks for souch a long answer.Gonna look all that.Still cant beleve lower fps with new gpu (if cpu is "problem" how come with 970gtx I had more fps)but freesync is dope!so smooth

As mentioned above the amd gpu drivers seem to stress the CPU more than the nvidia drivers. Since my overclocked 2600k struggles sometimes with 60 fps (in other situations I could output way over 200 fps), your non-overclocked CPU might struggle as well.
With the nvidia drivers it wasn't as bad and only now you see it.
So the new graphics card probably isn't the reason behind the lower fps numbers. Or at least not directly...

You really should monitor your gpu load and the CPU speeds. Maybe you can just raise the maximum turbo about 100 MHz and it's the same performance as before without the need to touch any voltages or other more complicated stuff

Oh, and always double check while reading if the first letter is a G or a C. I saw it causing massive misunderstandings etc in the past