Fix Mantle stuttering in BF4

[Headfoot]

Credit for this goes to Erenhardt who PM'd me with some details.

But between the 14.3 Catalyst betas and this I no longer have any stuttering in BF4. The trick is surprisingly simple: close all your background programs like you used to do back in the days before quad-core. It isn't that these programs are consuming your CPU cycles in any great number, rather it is that Mantle is closer to the metal and interrupt handling is likely not as thoughtfully implemented as it is from the OS itself (which I assume is what DX uses).

The only things I had running in the background were Skype, Dropbox, Skyrdive, Steam and a Multimonitor program -- nothing serious. But once closed it fixed it for me. That, and whatever modifications are present in Cat 14.3.

 

[Gloomy]

I mentioned this before.

http://forums.anandtech.com/showpost.php?p=36116442&postcount=99

Origin is a big offender. It wakes up occasionally and hits a single core for a few seconds, then goes back "asleep".

This causes a HUGE stutter.

I don't think it's because it's closer to the metal, rather that it's really utilizing the CPU unlike DX which just pushes two threads really hard and nothing else.

 

[Headfoot]

I mentioned this before.

http://forums.anandtech.com/showpost.php?p=36116442&postcount=99

Origin is a big offender. It wakes up occasionally and hits a single core for a few seconds, then goes back "asleep".

This causes a HUGE stutter.

I don't think it's because it's closer to the metal, rather that it's really utilizing the CPU unlike DX which just pushes two threads really hard and nothing else.

Thanks for that too. Of course Origin is making things worse, no surprises there lol

Anywho, when I say close to the metal I mean in a programming sense rather than overhead sense, in that it is my understanding that with Mantle you aren't relying on the OS scheduler as much/at all (correct me if I am wrong here) and so I doubt that the game devs are implementing OS-level interrupt handling in their game engines

Sidenote: regarding that post you linked, apparently now there is a console command for BF4 where you can limit the number of threads it will use in order to preserve a spare core for the rest of your system. You can even put it in a .cfg file that launches with the game each time. I haven't tried this yet but it seems I don't have to. " thread.maxprocessorcount [number] " I bet freeing up a core for less stuttering on Mantle was the original goal of this feature, though the average gamer seems to think it automagically makes BF4 use more cores by increasing the number

 

[Erenhardt]

I mentioned this before.

http://forums.anandtech.com/showpost.php?p=36116442&postcount=99

I believe we are not the only ones that found out about it.
Its quite amazing how much left there is on the table when using dx. Brings back the review that showed CPU performance while recording gameplay where fx8350 was the best cpu for the job, and worst then not recording.

Good look recording gameplay with mantle! (I believe you can't record mantle gameplay with FRAPS)

 

[OCGuy]

It would probably be a better idea to make sure AMD knows about your issues and fixes them in the next patch. Closing all background programs doesn't sound very practical.

I think I heard that disabling AA in-game, but forcing it in CCC may help.

 

[Ed1]

I mentioned this before.

http://forums.anandtech.com/showpost.php?p=36116442&postcount=99

Origin is a big offender. It wakes up occasionally and hits a single core for a few seconds, then goes back "asleep".

This causes a HUGE stutter.

I don't think it's because it's closer to the metal, rather that it's really utilizing the CPU unlike DX which just pushes two threads really hard and nothing else.

Problem is you can't close Origin with BF4 .
You shouldn't have to do this on modern multi-core system . Its why we have them so multitasking can run fine .
Of course you do need to be careful what is running in background but most processes don't do much and shouldn't affect game unless there cpu intensive or polling cpu .

 

[Midwayman]

Isn't it possible to force BF4 only to use 7 or 8 logical cores or something?

 

[HWfreak]

Credit for this goes to Erenhardt who PM'd me with some details.

But between the 14.3 Catalyst betas and this I no longer have any stuttering in BF4. The trick is surprisingly simple: close all your background programs like you used to do back in the days before quad-core. It isn't that these programs are consuming your CPU cycles in any great number, rather it is that Mantle is closer to the metal and interrupt handling is likely not as thoughtfully implemented as it is from the OS itself (which I assume is what DX uses).

The only things I had running in the background were Skype, Dropbox, Skyrdive, Steam and a Multimonitor program -- nothing serious. But once closed it fixed it for me. That, and whatever modifications are present in Cat 14.3.

What GPU do you have, how much Vram and what BF4 settings are you using?

 

[f1sherman]

Isn't it possible to force BF4 only to use 7 or 8 logical cores or something?

yup, there's that fix too
Processor Affinity in Task Manager

Mantle reminds me of early days of CPU multithreading in Source engine.
No issues in Thief though.

 

[144HzGamer]

Problem is you can't close Origin with BF4 .
You shouldn't have to do this on modern multi-core system . Its why we have them so multitasking can run fine .
Of course you do need to be careful what is running in background but most processes don't do much and shouldn't affect game unless there cpu intensive or polling cpu .

You could use Outcome:

What is Outcome?
Outcome is a free and easy way to play all of your favorite latest Origin™ games, without the need to actually have Origin™ running in the background. This allows for a more solid and optimal gameplay experience, relieving you from the stress of worrying about the memory footprint and processor usage that Origin™ generates.

http://outcome.nofate.me/

 

[Headfoot]

Isn't it possible to force BF4 only to use 7 or 8 logical cores or something?

Yes, check 3rd post in this thread

What GPU do you have, how much Vram and what BF4 settings are you using?

R9 290 @ 1025 Mhz, 5329x1050 @ Ultra (No MSAA, Low Post-AA). I get 60 fps with that in DX11 on most maps but I'll get some minimums in the 30's on particular maps in particular situations. When I close everything like I talked about in the OP I get 60 fps more frequently and my minimums don't drop as low.

It would probably be a better idea to make sure AMD knows about your issues and fixes them in the next patch. Closing all background programs doesn't sound very practical.

I think I heard that disabling AA in-game, but forcing it in CCC may help.

It's a problem on Dice's end more likely than not. I'll just close my programs instead of hoping DICE does something about it, who knows how long I'd end up waiting

 

[MeldarthX]

my stutter was do to not uninstall all of the old drivers......I don't see as good as gains as I would if I had 290........but 7870 LE is scary smooth now compaired to DX.....

 

[ASM-coder]

It's a problem on Dice's end more likely than not. I'll just close my programs instead of hoping DICE does something about it, who knows how long I'd end up waiting

Dice does know about it, or at least someone tweeted Repi about it a while back. There is a thread about this on battlelog

1. Ivan Marijanović ‏@191x7 Mar 8
   @Vincent0K @repi It seems that for some players Origin causes CPU Spikes while using Mantle in BF4. Some of us tested that, seems 2be true.
2. Johan Andersson ‏@repi Mar 8
   @191x7 @Vincent0K you mean when you have the Origin overlay enabled? do you have any thread about it?
3. Ivan Marijanović ‏@191x7 Mar 8
   @repi @Vincent0K Here you have a forum thread about it http://battlelog.battlefield.com/bf4/forum/threadview/2955065226272867132/ … -it manifests by just having Origin in background (must have).