Debian 11 - Gigabyte 78LMT-USB3 with AMD FX-8350 CPU cores count incorrect

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Bottleneck95140
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Debian 11 - Gigabyte 78LMT-USB3 with AMD FX-8350 CPU cores count incorrect

#1 Post by Bottleneck95140 »

Hi,

I am having a weird behaviour on my home Linux server running Debian 11(bullseye).

My hardware:
Motherboard: Gigabyte 78LMT-USB3
CPU: AMD fx-8350
Mem: 32GB
Disks: 6TB (LVM)


Kernel:
5.10.0-15-amd64

Server is fully updated at the OS level.

BIOS information:
BIOS#2.jpg
BIOS#2.jpg (483.08 KiB) Viewed 184 times

My problem:
I built this Linux server a few days ago to run Linux KVM and VMware Workstation. Every morning I boot my home server and every time I notice that the amount of cores drop to 2 from 8. See blow:
lscpu#1.jpg
lscpu#1.jpg (109.13 KiB) Viewed 184 times

I know that the lscpu command ran above is correct as the Virtual Machine on VMware workstation I want to start will display an error about the number of CPU cores available. This Virtual Machine was set with 2 CPU and 2 cores (4 cores in total), hence the error because there are just 2 cores available.

To resolve this issue, I had to access the BIOS (go to Advanced BIOS Features) then change and revert back one of the 2 setting below:
BIOS#4.jpg
BIOS#4.jpg (503.11 KiB) Viewed 185 times

Then, the CPU core count come back to the correct number (8):
(--Sorry, Debian forum limit to 3 pics attachment. I had to copy paste the lscpu result instead.--)
####################################################
patrick@debian:~$ lscpu
Architecture: x86_64
CPU op-mode(s): 32-bit, 64-bit
Byte Order: Little Endian
Address sizes: 48 bits physical, 48 bits virtual
CPU(s): 8
On-line CPU(s) list: 0-7
Thread(s) per core: 2
Core(s) per socket: 4
Socket(s): 1
NUMA node(s): 1
Vendor ID: AuthenticAMD
CPU family: 21
Model: 2
Model name: AMD FX(tm)-8350 Eight-Core Processor
Stepping: 0
Frequency boost: enabled
CPU MHz: 1398.017
CPU max MHz: 4000.0000
CPU min MHz: 1400.0000
BogoMIPS: 7999.75
Virtualization: AMD-V
L1d cache: 64 KiB
L1i cache: 256 KiB
L2 cache: 8 MiB
L3 cache: 8 MiB
NUMA node0 CPU(s): 0-7
Vulnerability Itlb multihit: Not affected
Vulnerability L1tf: Not affected
Vulnerability Mds: Not affected
Vulnerability Meltdown: Not affected
Vulnerability Spec store bypass: Mitigation; Speculative Store Bypass disabled via prctl and seccomp
Vulnerability Spectre v1: Mitigation; usercopy/swapgs barriers and __user pointer sanitization
Vulnerability Spectre v2: Mitigation; Retpolines, STIBP disabled, RSB filling
Vulnerability Srbds: Not affected
Vulnerability Tsx async abort: Not affected
Flags: fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ht syscall nx mmxext fxsr_opt pdpe1gb rdtscp lm constant_tsc rep_good nopl
nonstop_tsc cpuid extd_apicid aperfmperf pni pclmulqdq monitor ssse3 fma cx16 sse4_1 sse4_2 popcnt aes xsave avx f16c lahf_lm cmp_legacy svm extapic cr8_legacy abm sse4a mis
alignsse 3dnowprefetch osvw ibs xop skinit wdt lwp fma4 tce nodeid_msr tbm topoext perfctr_core perfctr_nb cpb hw_pstate ssbd vmmcall bmi1 arat npt lbrv svm_lock nrip_save t
sc_scale vmcb_clean flushbyasid decodeassists pausefilter pfthreshold
###################################################


At this stage, I can start my Virtual Machine without seeing a popup about the CPU cores count.

I am not really sure what's happening, a reboot on the same day still show the CPU with 8 cores but first thing in the morning a boot the following day shows the CPU with 2 cores only.

As per the link below, this motherboard (Gigabyte 78LMT-USB3) support this processor (AMD fx-8350):
https://www.cpu-upgrade.com/CPUs/AMD/FX ... oards.html


Am I missing something or am I doing something wrong?

Thank in advance for your answer.

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Re: Debian 11 - Gigabyte 78LMT-USB3 with AMD FX-8350 CPU cores count incorrect

#2 Post by Aki »

Hello,
Have you tried enabling only the “CPU Core 7-8” optional (and not the others) ?
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Re: Debian 11 - Gigabyte 78LMT-USB3 with AMD FX-8350 CPU cores count incorrect

#3 Post by LE_746F6D617A7A69 »

Bottleneck95140 wrote: 2022-06-22 12:22 To resolve this issue, I had to access the BIOS (go to Advanced BIOS Features) then change and revert back one of the 2 setting below: (...)

(...) a reboot on the same day still show the CPU with 8 cores but first thing in the morning a boot the following day shows the CPU with 2 cores only.
So it looks like the BIOS settings are preserved only until the next day -> start with replacing the CMOS Lithium battery (usually it's CR2032)
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Bottleneck95140
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Re: Debian 11 - Gigabyte 78LMT-USB3 with AMD FX-8350 CPU cores count incorrect

#4 Post by Bottleneck95140 »

Aki wrote: 2022-06-22 18:19 Hello,
Have you tried enabling only the “CPU Core 7-8” optional (and not the others) ?
Hi Aki,
Thank you for coming back to me. I am unable to enable "CPU core 7-8" only as I don't have the option to disable "CPU core 1-2".

Bottleneck95140
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Re: Debian 11 - Gigabyte 78LMT-USB3 with AMD FX-8350 CPU cores count incorrect

#5 Post by Bottleneck95140 »

LE_746F6D617A7A69 wrote: 2022-06-22 20:43
Bottleneck95140 wrote: 2022-06-22 12:22 To resolve this issue, I had to access the BIOS (go to Advanced BIOS Features) then change and revert back one of the 2 setting below: (...)

(...) a reboot on the same day still show the CPU with 8 cores but first thing in the morning a boot the following day shows the CPU with 2 cores only.
So it looks like the BIOS settings are preserved only until the next day -> start with replacing the CMOS Lithium battery (usually it's CR2032)
Hi LE_746F6D617A7A69,
Thank you for coming back to me. That's a really good point and this might be the root cause of this problem. However, when I boot my server in the morning the BIOS settings are identical as the day before and it does not seem that the BIOS settings are reset to the default setting.
I will get a new CR2032 battery and provide an update.

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Re: Debian 11 - Gigabyte 78LMT-USB3 with AMD FX-8350 CPU cores count incorrect

#6 Post by Bottleneck95140 »

Alright, I replaced the CMOS Lithium battery, boot the server and run the lscpu command. The count of CPU core is now 2 because of the removal of the CMOS battery, so the CMOS battery was probably the issue.
I went to the BIOS (Advanced BIOS Features) then change and revert back the setting for the "CPU core control". Save the CMOS setting to the BIOS. Then, boot the server, as expected I have now 8 CPU cores available.
Let see if the CPU core count will stay the same tomorrow morning.

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Re: Debian 11 - Gigabyte 78LMT-USB3 with AMD FX-8350 CPU cores count incorrect

#7 Post by LE_746F6D617A7A69 »

Bottleneck95140 wrote: 2022-06-23 11:59 The count of CPU core is now 2 because of the removal of the CMOS battery
Removing the CMOS battery effectively resets the BIOS to default settings -> it means that the default BIOS settings in Your MB are broken -> disabling multi-core support. This can also mean that the MB does not really support Your CPU, and it seems to be quite probable.

Why the settings seem to be unchanged?: 20 years ago You would get a message: "The CRC32 checksum of Your BIOS settings does not match - resetting to defaults", but today, such messages are disabled -> in case of problems with any part of the HW You are expected/forced to pay for support, and this is not a joke.
(that paid support is a joke, but that's a different topic)
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Re: Debian 11 - Gigabyte 78LMT-USB3 with AMD FX-8350 CPU cores count incorrect

#8 Post by NFT5 »

I've been running these motherboards and the FX CPUs for 10 years or more. At the peak, I had 6 of them (GA78LMT-USB3), plus a few more with the 970A-D3P motherboard. Most operated in my shop where the conditions were severe - hot in summer, cold in winter and dirty/dusty all year.

The motherboards are generally amongst the best. We ran exclusively Gigabyte simply because every other brand failed. The GA-78LMT-USB3 is an "Ultra Durable" board - meaning that it's made to take severe use and environments. It also offered all the "latest" features at the time like 1600GHz RAM, USB3 and 6 x SATA connectors.

However,

- I clean every machine thoroughly at least once a year. Cleaning means blowing out dust with compressed air and then washing all components on the motherboard and all contacts/connectors with contact cleaner then blowing dry. Machines in the dustier parts of the shop got this twice a year. Moral = keep it clean

- The FX processors run hot. Very hot when working hard. CPU should be removed, cleaned and new thermal paste applied every 1-2 years. If you allow the old paste to dry out you can get all kinds of strange behaviour, including what OP has experienced.

- The FX processors run hot. (Yes, again) The standard AMD coolers don't work well enough to keep these CPUs cool. I replaced all of them with Cooler Master Hyper TX3. Make sure your case is deep/wide enough - these coolers are BIG. But they work well. My server (970A-D3P + FX8350) is currently running at 15C (almost idling) and never gets over 40C. Strongly recommend to upgrade the case exhaust fan as well - you need to get that hot air out of there.

- This motherboard and CPU can be overclocked significantly and was a favourite with the "gamers" back in the day. My suggestion is: DON'T. You already have 8 cores at 4GHz and overclocking doesn't change the Bus. For the extra heat generated overclocking isn't worth it, IMHO, especially in a server role where processor speed isn't necessarily the most important factor and doesn't change built-in limitations like your SATA 3GB/s speeds.

- The GA-78LMT-USB3 motherboards were the later ones in the series that ran the AMD 760G chipset. These ran DDR3 RAM, but the earlier series had DDR2. The later ones are much better but some do need a BIOS update to operate with AM3+ CPUs. Make sure that you do this update if needed. In fact, do it whether needed or not, see next point.

- This motherboards has a dual BIOS, so a CMOS failure shouldn't have quite the same effect as on a board with single BIOS. But, if one chip is corrupted or damaged then, as above, a BIOS update would be recommended.

- CMOS batteries I used to change every 5 years or so. You've already done this but did you clear the CMOS? Even removing the battery doesn't necessarily clear the CMOS since it's protected with a backup capacitor. Short the "Clear CMOS" pins on the motherboard when you replace the battery.

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Re: Debian 11 - Gigabyte 78LMT-USB3 with AMD FX-8350 CPU cores count incorrect

#9 Post by LE_746F6D617A7A69 »

@NFT5:
I agree with most of what You've said, but there is one thing which is questionable (interesting?):
NFT5 wrote: 2022-06-24 01:40 My server (970A-D3P + FX8350) is currently running at 15C (almost idling) and never gets over 40C.
If by "15C" You mean 15 degrees Celsius, then what is the ambient temperature? - It's impossible to achieve temps lower than the ambient(*) - is Your server stored in a fridge?
Jokes aside - CPU manufacturers are known to report false CPU temps (lowered) - is it possible that this is the case here?

Fe: Currently My Ryzen 3700X is running at forced fixed frequency of 2.2GHz, cooler: Noctua NH-D14, ambient temp: 27 deg.C, CPU temp = 38 deg.C, fan speed = 590RPM -> i.e no matter how big the radiator is, it's impossible to have the CPU temp below the environment temperature.

(*) unless a dedicated thermal pump is used.
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Re: Debian 11 - Gigabyte 78LMT-USB3 with AMD FX-8350 CPU cores count incorrect

#10 Post by sunrat »

LE_746F6D617A7A69 wrote: 2022-06-24 21:03 @NFT5:
I agree with most of what You've said, but there is one thing which is questionable (interesting?):
NFT5 wrote: 2022-06-24 01:40 My server (970A-D3P + FX8350) is currently running at 15C (almost idling) and never gets over 40C.
If by "15C" You mean 15 degrees Celsius, then what is the ambient temperature? - It's impossible to achieve temps lower than the ambient(*) - is Your server stored in a fridge?
I was wondering about that too, 15°C seems rather fantastic. My i5 6500 idles at around 30°C with 20°C ambient. Only stock cooler and 2 case fans.

Also I have found Gigabyte mobos to be very reliable, ever since my last ASUS one died a few weeks after the warranty ran out about 14 years ago. Still have an ASUS graphics card which has been good for ~6 years.
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Re: Debian 11 - Gigabyte 78LMT-USB3 with AMD FX-8350 CPU cores count incorrect

#11 Post by NFT5 »

LE_746F6D617A7A69 wrote: 2022-06-24 21:03 is Your server stored in a fridge?
:lol: :lol: No. Ambient yesterday was about 11C at that time, so idling at a few degrees over that isn't so unbelievable. Temperatures go up pretty quick once it starts to do some work, though. The cooler limits these to about 40C when I used to regularly see 70C+ with the standard cooler. I don't think it's misreporting the temperatures. Not long since it was last cleaned and clean fins on the cooler plus a good fan can keep temperatures quite low. Wind can reduce apparent temperatures well below ambient, as you'd know.

Right now, ambient 12C:

Image

By comparison, my desktop Ryzen5 1600AF, which sits right next to the server:

Image

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