AMD bios settings

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Espionage724
Posts: 6
Joined: 13 Jul 2022, 15:45

Re: AMD bios settings

Post by Espionage724 » 13 Jul 2022, 15:54

Resizable BAR and Above 4G Decode options should be tested. Performance overall wasn't negatively affected, but Above 4G Decode by itself caused my mouse to feel more floaty.

IOMMU I'm not sure about. Some documentation says to keep it enabled in order to have device resources allocated properly, while community-based reports are that it increases latency. On Windows I keep it off, but I tend to keep it enabled on Linux.

Mode0 under CBS is probably the most mysterious option available. Someone on a forum somewhere reported that to AMD internally, it's related to something under Linux and lowering bandwidth. I've done Geekbench on Windows and found it consistently lowered performance if it was enabled. I believe Auto defaults to enabled, but I disable it in all cases.

Tuhin Lavania
Posts: 59
Joined: 21 Feb 2022, 09:26

Re: AMD bios settings

Post by Tuhin Lavania » 13 Jul 2022, 21:52

Slender wrote:
13 Jul 2022, 15:03
Tuhin Lavania wrote:
13 Jul 2022, 12:51
I tried some of the OP settings and they seem to have an effect on the input lag i was facing in Halo Infinite. I have playd around 20 matches to come to this conclusion.

I will add to this. I have a 5950x and putting Core levelling mode to 4 and on one CCD really decreases a lot of latency. So basically i have 12 cores disabled and i play on 4 cores on a 5950X.
???
5950x have 8+8 ccd, just disable 1ccd and give like 5800x.
lol
Actually no. Those 8 cores are still not local to each other. 4 cores enabled gives me lowest dpc latency numbers and the difference is drastic.
Core levelling Mode - 4 is unique in this way as these cores are local and there is negligible intercore latency between them.

Slender
Posts: 573
Joined: 25 Jan 2020, 17:55

Re: AMD bios settings

Post by Slender » 14 Jul 2022, 06:12

Tuhin Lavania wrote:
13 Jul 2022, 21:52
Slender wrote:
13 Jul 2022, 15:03
Tuhin Lavania wrote:
13 Jul 2022, 12:51
I tried some of the OP settings and they seem to have an effect on the input lag i was facing in Halo Infinite. I have playd around 20 matches to come to this conclusion.

I will add to this. I have a 5950x and putting Core levelling mode to 4 and on one CCD really decreases a lot of latency. So basically i have 12 cores disabled and i play on 4 cores on a 5950X.
???
5950x have 8+8 ccd, just disable 1ccd and give like 5800x.
lol
Actually no. Those 8 cores are still not local to each other. 4 cores enabled gives me lowest dpc latency numbers and the difference is drastic.
Core levelling Mode - 4 is unique in this way as these cores are local and there is negligible intercore latency between them.
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Tuhin Lavania
Posts: 59
Joined: 21 Feb 2022, 09:26

Re: AMD bios settings

Post by Tuhin Lavania » 14 Jul 2022, 06:46

Like i said above, 4 cores give me lowest dpc latency numbers and ive seen the picture you posted earlier. If you have a 5950x please try for yourself and update.

kokkatc
Posts: 108
Joined: 23 Mar 2017, 13:49

Re: AMD bios settings

Post by kokkatc » 14 Jul 2022, 15:29

Espionage724 wrote:
13 Jul 2022, 15:54
Resizable BAR and Above 4G Decode options should be tested. Performance overall wasn't negatively affected, but Above 4G Decode by itself caused my mouse to feel more floaty.

IOMMU I'm not sure about. Some documentation says to keep it enabled in order to have device resources allocated properly, while community-based reports are that it increases latency. On Windows I keep it off, but I tend to keep it enabled on Linux.

Mode0 under CBS is probably the most mysterious option available. Someone on a forum somewhere reported that to AMD internally, it's related to something under Linux and lowering bandwidth. I've done Geekbench on Windows and found it consistently lowered performance if it was enabled. I believe Auto defaults to enabled, but I disable it in all cases.
I've always wondered this ever since they added gpu scheduling. It always felt like whenever I enabled these settings my hit detection was off. I'll see if I can run some tests and report back if I find anything fishy.

Slender
Posts: 573
Joined: 25 Jan 2020, 17:55

Re: AMD bios settings

Post by Slender » 14 Jul 2022, 20:10

Tuhin Lavania wrote:
14 Jul 2022, 06:46
Like i said above, 4 cores give me lowest dpc latency numbers and ive seen the picture you posted earlier. If you have a 5950x please try for yourself and update.
you use smt?

Tuhin Lavania
Posts: 59
Joined: 21 Feb 2022, 09:26

Re: AMD bios settings

Post by Tuhin Lavania » 14 Jul 2022, 22:21

Slender wrote:
14 Jul 2022, 20:10
Tuhin Lavania wrote:
14 Jul 2022, 06:46
Like i said above, 4 cores give me lowest dpc latency numbers and ive seen the picture you posted earlier. If you have a 5950x please try for yourself and update.
you use smt?
No SMT is disabled. I tried Core levelling mode to Seven and then Automatic ( 8 cores enabled ) and i could see a small increase in dpc latency numbers. How much that translates in game i dont know but i need a lowest number which i get while 4 cores are enabled.
I tried this earlier but since you were so sure that the latency wont increase, i tried it again. There is not a big, but a small increase in dpc latency. With 4 cores enabled i still get 170-180fps in Halo in 4v4.

User avatar
Espionage724
Posts: 6
Joined: 13 Jul 2022, 15:45

Re: AMD bios settings

Post by Espionage724 » 15 Jul 2022, 16:42

Tuhin Lavania wrote:
14 Jul 2022, 22:21
Slender wrote:
14 Jul 2022, 20:10
Tuhin Lavania wrote:
14 Jul 2022, 06:46
Like i said above, 4 cores give me lowest dpc latency numbers and ive seen the picture you posted earlier. If you have a 5950x please try for yourself and update.
you use smt?
No SMT is disabled.
I don't know how it reacts on different platforms and CPUs, but with my 2700X if I disable SMT, my NVMe drive gets half the IRQs assigned to it. I'm not sure why this happens or what else may be affected.

Alpha
Posts: 132
Joined: 09 Jul 2020, 17:58

Re: AMD bios settings

Post by Alpha » 19 Jul 2022, 10:28

Espionage724 wrote:
15 Jul 2022, 16:42
Tuhin Lavania wrote:
14 Jul 2022, 22:21
Slender wrote:
14 Jul 2022, 20:10
Tuhin Lavania wrote:
14 Jul 2022, 06:46
Like i said above, 4 cores give me lowest dpc latency numbers and ive seen the picture you posted earlier. If you have a 5950x please try for yourself and update.
you use smt?
No SMT is disabled.
I don't know how it reacts on different platforms and CPUs, but with my 2700X if I disable SMT, my NVMe drive gets half the IRQs assigned to it. I'm not sure why this happens or what else may be affected.
SMT disabled made COD unplayable but other games were good to go. Pretty incredible improvement with these settings otherwise and I didn't really have any complaints before but it made a massive difference. Board right now Asus Dark Hero VIII. Thanks all!

Shade7
Posts: 222
Joined: 25 May 2022, 18:44

Re: AMD bios settings

Post by Shade7 » 19 Jul 2022, 13:57

Alpha wrote:
19 Jul 2022, 10:28
Espionage724 wrote:
15 Jul 2022, 16:42
Tuhin Lavania wrote:
14 Jul 2022, 22:21
Slender wrote:
14 Jul 2022, 20:10


you use smt?
No SMT is disabled.
I don't know how it reacts on different platforms and CPUs, but with my 2700X if I disable SMT, my NVMe drive gets half the IRQs assigned to it. I'm not sure why this happens or what else may be affected.
SMT disabled made COD unplayable but other games were good to go. Pretty incredible improvement with these settings otherwise and I didn't really have any complaints before but it made a massive difference. Board right now Asus Dark Hero VIII. Thanks all!
Which other games did it improve?

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