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adding 16G to 16G memory yields 24G: can you find missing 8G?
adding 16G to 16G memory yields 24G: can you find missing 8G?
I think this is a generic problem with acpi bios, maybe just Dell.
(Suse leap42.1 on Dell t7400, Linux linux-2v1c 4.1.34-33-default #1 SMP
PREEMPT Thu Oct 20 08:03:29 UTC 2016 (fe18aba) x86_64 x86_64 x86_64 GNU/Linux)
I recently added 16G of Hynix memory (HYMP151F72CP4N3-Y5) to a Dell t7400 workstation that contained 16G
of memory as originally shipped (M395T5166AZ4-CE65).
dmidecode -t 17 | grep Size | grep MB
Size: 4096 MB
Size: 4096 MB
Size: 4096 MB
Size: 4096 MB
Size: 4096 MB
Size: 4096 MB
Size: 4096 MB
Size: 4096 MB
Also, the Dell mboard ACPI bios sees all 32G. Memtest passes on all 8 memory modules of 4mb
each. (So reordering or reseating the memory modules won't solve this. I
tried this already.)
I'm using the last bios posted to Dell's support pages:
>dmidecode -s bios-version
A0
>dmidecode -s bios-release-date
05/23/20119
After I boot into linux, the system sees only 24G.
dmesg:
[ 0.000000] e820: BIOS-provided physical RAM map:
[ 0.000000] BIOS-e820: [mem 0x0000000000000000-0x000000000009c3ff] usable
[ 0.000000] BIOS-e820: [mem 0x00000000000f0000-0x00000000000fffff] reserved
[ 0.000000] BIOS-e820: [mem 0x0000000000100000-0x00000000cfe0abff] usable
[ 0.000000] BIOS-e820: [mem 0x00000000cfe0ac00-0x00000000cfe5cbff] ACPI NVS
[ 0.000000] BIOS-e820: [mem 0x00000000cfe5cc00-0x00000000cfe5ebff] ACPI data
[ 0.000000] BIOS-e820: [mem 0x00000000cfe5ec00-0x00000000cfffffff] reserved
[ 0.000000] BIOS-e820: [mem 0x00000000e0000000-0x00000000efffffff] reserved
[ 0.000000] BIOS-e820: [mem 0x00000000fe000000-0x00000000feffffff] reserved
[ 0.000000] BIOS-e820: [mem 0x00000000ffb00000-0x00000000ffffffff] reserved
[ 0.000000] BIOS-e820: [mem 0x0000000100000000-0x000000062fffffff] usable
which is only 26575110143 bytes!
>free -m
total used free shared buffers cached
Mem: 24109 6941 17167 38 577 4225
>grep line /sys/devices/system/memory/*/state -> all online
But memory26-29 are not detected: total lines = 192. Why? 192x8M -> 24G
only. But 4x8M -> 32M, not enough to account for the missing ram. Are
memory26-29 reserved?
>dmesg | grep eserved
[ 0.000000] BIOS-e820: [mem 0x00000000000f0000-0x00000000000fffff] reserved
[ 0.000000] BIOS-e820: [mem 0x00000000cfe5ec00-0x00000000cfffffff] reserved
[ 0.000000] BIOS-e820: [mem 0x00000000e0000000-0x00000000efffffff] reserved
[ 0.000000] BIOS-e820: [mem 0x00000000fe000000-0x00000000feffffff] reserved
[ 0.000000] BIOS-e820: [mem 0x00000000ffb00000-0x00000000ffffffff] reserved
[ 0.000000] e820: update [mem 0x00000000-0x00000fff] usable ==> reserved
[ 0.000000] e820: update [mem 0xcff00000-0xffffffff] usable ==> reserved
[ 0.000000] DMA zone: 21 pages reserved
[ 0.000000] Memory: 24672120K/25163412K available (6571K kernel code, 1086K
rwdata, 4856K rodata, 1560K init, 1520K bss, 491292K reserved, 0K
cma-reserved)
Looks like the reserved memory is not nearly enough to account for the
discrepancy.
MTRR?
>dmesg | grep MTRR
[ 0.000000] MTRR default type: uncachable
[ 0.000000] MTRR fixed ranges enabled:
[ 0.000000] MTRR variable ranges enabled:
dmesg gives no warnings.
This machine also runs an ancient copy of Windows Vista Business. That
produces the same pattern: the bios sees all 32G but the OS only 24.
Adding the boot parameter mem=32G has no effect (because, by the point that
the boot process loads the kernel, the visible memory is already reduced).
So apparently something happened when the bios created the physical ram map.
Which causes the loss of 8G?
(Suse leap42.1 on Dell t7400, Linux linux-2v1c 4.1.34-33-default #1 SMP
PREEMPT Thu Oct 20 08:03:29 UTC 2016 (fe18aba) x86_64 x86_64 x86_64 GNU/Linux)
I recently added 16G of Hynix memory (HYMP151F72CP4N3-Y5) to a Dell t7400 workstation that contained 16G
of memory as originally shipped (M395T5166AZ4-CE65).
dmidecode -t 17 | grep Size | grep MB
Size: 4096 MB
Size: 4096 MB
Size: 4096 MB
Size: 4096 MB
Size: 4096 MB
Size: 4096 MB
Size: 4096 MB
Size: 4096 MB
Also, the Dell mboard ACPI bios sees all 32G. Memtest passes on all 8 memory modules of 4mb
each. (So reordering or reseating the memory modules won't solve this. I
tried this already.)
I'm using the last bios posted to Dell's support pages:
>dmidecode -s bios-version
A0
>dmidecode -s bios-release-date
05/23/20119
After I boot into linux, the system sees only 24G.
dmesg:
[ 0.000000] e820: BIOS-provided physical RAM map:
[ 0.000000] BIOS-e820: [mem 0x0000000000000000-0x000000000009c3ff] usable
[ 0.000000] BIOS-e820: [mem 0x00000000000f0000-0x00000000000fffff] reserved
[ 0.000000] BIOS-e820: [mem 0x0000000000100000-0x00000000cfe0abff] usable
[ 0.000000] BIOS-e820: [mem 0x00000000cfe0ac00-0x00000000cfe5cbff] ACPI NVS
[ 0.000000] BIOS-e820: [mem 0x00000000cfe5cc00-0x00000000cfe5ebff] ACPI data
[ 0.000000] BIOS-e820: [mem 0x00000000cfe5ec00-0x00000000cfffffff] reserved
[ 0.000000] BIOS-e820: [mem 0x00000000e0000000-0x00000000efffffff] reserved
[ 0.000000] BIOS-e820: [mem 0x00000000fe000000-0x00000000feffffff] reserved
[ 0.000000] BIOS-e820: [mem 0x00000000ffb00000-0x00000000ffffffff] reserved
[ 0.000000] BIOS-e820: [mem 0x0000000100000000-0x000000062fffffff] usable
which is only 26575110143 bytes!
>free -m
total used free shared buffers cached
Mem: 24109 6941 17167 38 577 4225
>grep line /sys/devices/system/memory/*/state -> all online
But memory26-29 are not detected: total lines = 192. Why? 192x8M -> 24G
only. But 4x8M -> 32M, not enough to account for the missing ram. Are
memory26-29 reserved?
>dmesg | grep eserved
[ 0.000000] BIOS-e820: [mem 0x00000000000f0000-0x00000000000fffff] reserved
[ 0.000000] BIOS-e820: [mem 0x00000000cfe5ec00-0x00000000cfffffff] reserved
[ 0.000000] BIOS-e820: [mem 0x00000000e0000000-0x00000000efffffff] reserved
[ 0.000000] BIOS-e820: [mem 0x00000000fe000000-0x00000000feffffff] reserved
[ 0.000000] BIOS-e820: [mem 0x00000000ffb00000-0x00000000ffffffff] reserved
[ 0.000000] e820: update [mem 0x00000000-0x00000fff] usable ==> reserved
[ 0.000000] e820: update [mem 0xcff00000-0xffffffff] usable ==> reserved
[ 0.000000] DMA zone: 21 pages reserved
[ 0.000000] Memory: 24672120K/25163412K available (6571K kernel code, 1086K
rwdata, 4856K rodata, 1560K init, 1520K bss, 491292K reserved, 0K
cma-reserved)
Looks like the reserved memory is not nearly enough to account for the
discrepancy.
MTRR?
>dmesg | grep MTRR
[ 0.000000] MTRR default type: uncachable
[ 0.000000] MTRR fixed ranges enabled:
[ 0.000000] MTRR variable ranges enabled:
dmesg gives no warnings.
This machine also runs an ancient copy of Windows Vista Business. That
produces the same pattern: the bios sees all 32G but the OS only 24.
Adding the boot parameter mem=32G has no effect (because, by the point that
the boot process loads the kernel, the visible memory is already reduced).
So apparently something happened when the bios created the physical ram map.
Which causes the loss of 8G?
theflash1932
7 Technologist
7 Technologist
•
16.3K Posts
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November 2nd, 2016 12:00
Make sure memory is set to optimized mode in the BIOS. Sparing or mirroring will cause some memory to not be made available to the OS.
jbennett0
14 Posts
0
November 2nd, 2016 15:00
There is no such setting in the Dell bios
RoHe
10 Elder
10 Elder
•
43.5K Posts
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November 2nd, 2016 16:00
Exactly which version of BIOS are you running? There's no "A0" version. According to the Support site, A11 is latest version for the T7400.
jbennett0
14 Posts
0
November 2nd, 2016 21:00
A09
I don't know how the digit 9 got truncated.
RoHe
10 Elder
10 Elder
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43.5K Posts
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November 3rd, 2016 11:00
And you don't have the latest version of BIOS.
jbennett0
14 Posts
0
November 3rd, 2016 12:00
From Dell product support
"Precision T7400
Service Tag:
<ADMIN NOTE: Service tag removed per privacy policy>
| Express Service Code:
<ADMIN NOTE: Express service code removed per privacy policy>
...
The product you’ve selected does not have or require updates."
RoHe
10 Elder
10 Elder
•
43.5K Posts
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November 3rd, 2016 13:00
Edit your last post ASAP and remove the Service Tag and ESC. Never post either of them in an open forum like this. and treat them the way you treat other confidential info.
The Support site is malfunctioning today (11-03-16) so I wouldn't believe that. When I looked yesterday, BIOS A11 was listed as the latest, and their ftp site shows BIOS A10 and A11 were released after A09 (but those download links aren't working today, either).
Don't know if either one of those will fix the problem you're experiencing, or if maybe there's an issue with the chipset driver you're using since BIOS sees all installed RAM, and that's before the OS and chipset drivers are loaded.
jbennett0
14 Posts
0
November 4th, 2016 11:00
Yes, thanks, I just d'loaded the 2 chipset and 1 bios drivers.
I'll try them in a bit, running linux now.
jim
RoHe
10 Elder
10 Elder
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43.5K Posts
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November 4th, 2016 11:00
The Support site is working again, so you should be able to get BIOS A11 and latest Intel chipset drivers for Windows, if you need them.
RoHe
10 Elder
10 Elder
•
43.5K Posts
0
November 4th, 2016 13:00
You may need to go to Intel's download site and use their wizard (assuming it works with Linux) to see if there's a suitable Linus chipset driver for your hardware...
jbennett0
14 Posts
0
November 5th, 2016 17:00
Hmmm. Both Vista and Linux show exactly the same symptom: bios sees 32G, OS sees 24.
My other computer is a Dell 670 with 2 xeons: OS sees both processors and memory correctly.
Here's an update:
I let a current version of memtest86+ run all night -- no
errors. Then I applied the latest Dell Bios and chipset updates from within Vista.
Summary: SuSE linux Leap 42.1 continues to boot just fine, but still sees
only 24G of 32G memory. Vista Business 64-bit now manages to boot about every
other attempt, but once functioning it still sees only 24G of 32G memory (but
only one of 2 xeon processors! Did it ever see both? Not sure since I only
keep it around for one application which is rarely executed).
Along the way: Vista engaged in several crash dumps, rebooting, ineffectual
"startup repairs", and general unpredictability. Took a *long* time.
I am wondering if anyone has a t7400 workstation with more than 24G memory and
2 processors running 64-bit Vista Business?
RoHe
10 Elder
10 Elder
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43.5K Posts
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November 5th, 2016 18:00
Possibly the new RAM is incompatible ..??
jbennett0
14 Posts
0
November 5th, 2016 19:00
I think that has been investigated:
If incompatible, why does it see 8 but not 16G of the new ram?
If incompatible, why does it not matter into which slots I put the new ram? E.g.,
old old new new -> 24G
old new old new -> 24G
new new old old -> 24G
Now in a different linux thread, someone using risers said that the order was important to
proper functioning, but I think I'[ve covered the possible cases.