FX-8350: Trying to understand why disabling cores improves game performance

So a computer i built for my brother a while back which has an FX-8350 and 16gb RAM (and a more recent addition, a 980ti), seems to have some odd issues. It mostly plays everything great including BF4, Darksiders 2, RB6: Siege, etc. However, when The Division launched he encountered some issues. Basically the game would run great, 80-90+fps at 1080p ultra with a 144hz monitor, then every few minutes there would be lag and a big FPS drop to less than 10 fps that would last about 30 seconds, then back to normal. Rinse, repeat. Made the game unenjoyable. Through some research we discovered that going into task manager and setting core affinity on the game exe to only use 4 cores (0, 1, 2, 3) caused the game to run perfectly fine. There was a slight FPS hit, but the performance smoothed out.

We thought this was an isolated incident until BF1 came out. The beta ran fine, however the final release doesn't. He downloaded it and jumped on yesterday and the same exact issues as The Division cropped up. Updated drivers, tried different settings in the nvidia control panel, etc to no avail. I figured it was bottlenecking so i told him to go into bf1 and crank up the graphical scaling to put a heavier load on the GPU to give the CPU a chance to catch up better. He maxed it out to 200% and said it was running better, but the issue eventually returned. So then i remembered the core affinity trick from The Division. He did it, and it worked and everything ran great after that. I figured maybe turning cores off that way allowed it to turbo up higher on the remaining cores, but im not sure thats accurate.

Any idea why this is a fix? Why this is happening?

Also, what BIOS settings would i need to look at to try to force all cores to run at the max turbo frequency all the time? Motherboard is an ASRock 970 Extreme 4 i think. I feel like going this route would also stabilize/smooth things out, and if it doesn't its at least worth a try.

Is he running windows 10 or 7
I only had issues with one game in the past. That was Prototype2 and it was just a glitch in the gamefor anything over 4 cores. Could be core utilisation which is why I asked about Windows version. There were a couple hotfixes for Win7 to help the scheduler get along with piledriver

Windows 10, forgot to mention that sorry.

BF1 is fairly new might just need the newest driver from Nvidia which i saw was just released

Johan45 said:

BF1 is fairly new might just need the newest driver from Nvidia which i saw was just released

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The newest driver was used. I understand BF1 is new but The Division isn't anymore and the issue is still happening with that game, since launch even. I have a friend that was playing BF1 with a 670 and an FX-6100 that wasn't having this issue either (though its a pretty radical difference between a 670 and a 980ti, however the CPU isn't all that different and thats where the affinity fix comes into play for the 8-core).

How much ram is he using, are those games ram intensive.

PC's are having trouble with FPS using DX12 in BF1, so use DX11. Techspot Link: http://www.techspot.com/review/1267-battlefield-1-benchmarks/page4.html

Some game engines do better with 4 cores.

Johan45 said:

How much ram is he using, are those games ram intensive.

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Less than 8gb so far. He has 16gb so it shouldn't be an issue.

wingman99 said:

PC's are having trouble with FPS using DX12 in BF1, so use DX11. Techspot Link: http://www.techspot.com/review/1267-battlefield-1-benchmarks/page4.html

Some game engines do better with 4 cores.

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I totally agree with you there, but at my LAN party this past saturday i had a variety of setups there including i5s, i7s, i3s, xeons, and FX processors. The guy with an i7-2600k had a similar issue in bf1 and made some adjustments in nvidia control panel (and thus we tried those on the fx-8350 system to no avail), and thats it. Game ran fine for everyone else, and it became apparent the guys with the i5 and the i3 weren't performing as well as the i7 folks (especially the i3 of course, hes eyeballing a 4790k now).

Could it be VRMs overheating and causing throttling? The case is a Cooler Master HAF 932 and it has ridiculous airflow so i was hoping VRMs wouldn't have an issue.

Helgaiden said:

Less than 8gb so far. He has 16gb so it shouldn't be an issue.



I totally agree with you there, but at my LAN party this past saturday i had a variety of setups there including i5s, i7s, i3s, xeons, and FX processors. The guy with an i7-2600k had a similar issue in bf1 and made some adjustments in nvidia control panel (and thus we tried those on the fx-8350 system to no avail), and thats it. Game ran fine for everyone else, and it became apparent the guys with the i5 and the i3 weren't performing as well as the i7 folks (especially the i3 of course, hes eyeballing a 4790k now).

Could it be VRMs overheating and causing throttling? The case is a Cooler Master HAF 932 and it has ridiculous airflow so i was hoping VRMs wouldn't have an issue.

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If the VRMs are overheating the clock speed would reduce for Intel, I don't know about AMD. What is your CPU utilization at idle? Mine is 0-3%.

It could be throttling due too the mobo. The vrm section on that board is only 4 phases which tends to be weak for an 8 core FX processor.

You would have to run some tests to see if this is the case.

Nice catch Lochekey. That could quite easily be the issue

Helgaiden said:

Could it be VRMs overheating and causing throttling? The case is a Cooler Master HAF 932 and it has ridiculous airflow so i was hoping VRMs wouldn't have an issue.

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Lochekey said:

It could be throttling due too the mobo. The vrm section on that board is only 4 phases which tends to be weak for an 8 core FX processor.

You would have to run some tests to see if this is the case.

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Johan45 said:

Nice catch Lochekey. That could quite easily be the issue

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Yes i was wondering about this as well. Will have to sit down with the computer and put it under stress and watch the GHZ to verify. Until then, i have advised my brother to flip the rear fan from being an exhaust to being an intake so it hopefully blows over the VRMs better. But there is a massive fan on the side panel working as an intake blowing air in as well, was really hoping any parts having issues wouldn't be heat related. Oh well, we'll see.

Check in BIOS that HPC is enabled and APM disabled if the options are there

Try dropping the voltage on the fx 8350 and see if performance goes up. Also add an actual fan for just the mosfets.

also make sure cpu isnt overheating and throttling? would make sense if it takes a while for it to hapen. i didnt see temps mentioned anywhere in the thread.

Helgaiden said:

Yes i was wondering about this as well. Will have to sit down with the computer and put it under stress and watch the GHZ to verify. Until then, i have advised my brother to flip the rear fan from being an exhaust to being an intake so it hopefully blows over the VRMs better. But there is a massive fan on the side panel working as an intake blowing air in as well, was really hoping any parts having issues wouldn't be heat related. Oh well, we'll see.

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cdawall said:

Try dropping the voltage on the fx 8350 and see if performance goes up. Also add an actual fan for just the mosfets.

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good tips, will try these as soon as i can. Hopefully flipping the rear fan to an intake will blow enough over the VRMs though, its a 120mm fan back there i believe. Maybe 140mm.

wagex said:

also make sure cpu isnt overheating and throttling? would make sense if it takes a while for it to hapen. i didnt see temps mentioned anywhere in the thread.

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It definitely isn't overheating. Doesn't even really break the 40s C under load. That would have been my first thought but after some temp issues a while back with a different case, my brother went nuts with an Arctic A30 HSF and a Cooler Master HAF 932 with ridiculous airflow.

If temps are good see my earlier post. That helps throttling due to power draw

Johan45 said:

If temps are good see my earlier post. That helps throttling due to power draw

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Will do.

Being that his motherboard is a 970 and not a 990FX it is not the best for a high-powered an 8-core CPU. The 990FXs have an 8+2 power phase setup, while this mobo (as previously mentioned) is only a 4+1. As recommended by others it is almost mandatory that he put some kind of fan blowing directly on the VRMs - he could try laying a slot cooler on the backplate of the GPU to blow right onto the VRM heatsinks. Users of 970 mobos have reported FPS drops for demanding games, with noticeable choppiness and sometimes lag due probably to the 4+1 power setup and inferior VRMs compared to what you typically find on a 990FX mobo. I also read a user of your brother's mobo report that setting "TURBOCORE" in the BIOS actually worsened his gaming performance but that sounds a bit odd to me.

DaveB said:

Being that his motherboard is a 970 and not a 990FX it is not the best for a high-powered an 8-core CPU. The 990FXs have an 8+1 power phase setup, while this mobo (as previously mentioned) is only a 4+1. As recommended by others it is almost mandatory that he put some kind of fan blowing directly on the VRMs - he could try laying a slot cooler on the backplate of the GPU to blow right onto the VRM heatsinks. Users of 970 mobos have reported FPS drops for demanding games, with noticeable choppiness and sometimes lag due probably to the 4+1 power setup and inferior VRMs compared to what you typically find on a 990FX mobo. I also read a user of your brother's mobo report that setting "TURBOCORE" in the BIOS actually worsened his gaming performance but that sounds a bit odd to me.

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There are 990FX boards that have bad mosfet designs and 970 boards with good ones. Depends on board entirely the particular one mentioned has a 4+1 phase design which isn't the best, but it is only an 8350 and with some tweaking it can be fine.