Only half of RAM is seen
I have two Crucial RAM sticks which I put in two slots which are supposed to work dual-channel. BIOS sees both of them, but in total is showing only half:
CPU-Z shows 8GB of RAM, but Windows 10 only 4. If I put the sticks in single channel mode (slots A1/A2 for example) all 8GB are recognized by Windows.
Is this a main board failure and nothing can be done?
Changing the frequency does not help. As putting the sticks in other slots:
Here is part of CPU-Z report:
Chipset
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Northbridge AMD K15 IMC rev. 00
Southbridge AMD A88X FCH rev. 2.6
Graphic Interface PCI-Express
PCI-E Link Width x0
PCI-E Max Link Width x0
Memory Type DDR3
Memory Size 8 GBytes
Channels Single
Memory Frequency 666.5 MHz (3:20)
CAS# latency (CL) 9.0
RAS# to CAS# delay (tRCD) 9
RAS# Precharge (tRP) 9
Cycle Time (tRAS) 24
Bank Cycle Time (tRC) 29
Uncore Frequency 1799.6 MHz
Memory SPD
-------------------------------------------------------------------------
DIMM # 1
SMBus address 0x50
Memory type DDR3
Module format UDIMM
Manufacturer (ID) Crucial Technology (7F7F7F7F7F9B0000000000)
Size 4096 MBytes
Max bandwidth PC3-10700H (667 MHz)
Part number BLT4G3D1869DT1TX0.
Serial number A4133449
Number of banks 8
Nominal Voltage 1.50 Volts
EPP no
XMP yes
XMP revision 1.3
AMP no
JEDEC timings table CL-tRCD-tRP-tRAS-tRC @ frequency
JEDEC #1 6.0-6-6-16-22 @ 444 MHz
JEDEC #2 8.0-8-8-22-30 @ 592 MHz
JEDEC #3 9.0-9-9-24-33 @ 666 MHz
XMP profile XMP-1866
Specification PC3-14900
Voltage level 1.500 Volts
Min Cycle time 1.071 ns (933 MHz)
Max CL 9.0
Min tRP 9.43 ns
Min tRCD 9.43 ns
Min tWR 15.00 ns
Min tRAS 28.14 ns
Min tRC 49.50 ns
Min tRFC 160.00 ns
Min tRTP 7.50 ns
Min tRRD 6.00 ns
Command Rate 2T
XMP timings table CL-tRCD-tRP-tRAS-tRC-CR @ frequency (voltage)
XMP #1 6.0-6-6-18-32-2T @ 636 MHz (1.500 Volts)
XMP #2 7.0-7-7-21-37-2T @ 742 MHz (1.500 Volts)
XMP #3 8.0-8-8-24-42-2T @ 848 MHz (1.500 Volts)
XMP #4 9.0-9-9-27-47-2T @ 933 MHz (1.500 Volts)
XMP #5 10.0-9-9-27-47-2T @ 933 MHz (1.500 Volts)
DIMM # 2
SMBus address 0x51
Memory type DDR3
Module format UDIMM
Manufacturer (ID) Crucial Technology (7F7F7F7F7F9B0000000000)
Size 4096 MBytes
Max bandwidth PC3-10700H (667 MHz)
Part number BLT4G3D1869DT1TX0.
Serial number A019CA21
Number of banks 8
Nominal Voltage 1.50 Volts
EPP no
XMP yes
XMP revision 1.3
AMP no
JEDEC timings table CL-tRCD-tRP-tRAS-tRC @ frequency
JEDEC #1 6.0-6-6-16-22 @ 444 MHz
JEDEC #2 8.0-8-8-22-30 @ 592 MHz
JEDEC #3 9.0-9-9-24-33 @ 666 MHz
XMP profile XMP-1866
Specification PC3-14900
Voltage level 1.500 Volts
Min Cycle time 1.071 ns (933 MHz)
Max CL 9.0
Min tRP 9.43 ns
Min tRCD 9.43 ns
Min tWR 15.00 ns
Min tRAS 28.14 ns
Min tRC 49.50 ns
Min tRFC 160.00 ns
Min tRTP 7.50 ns
Min tRRD 6.00 ns
Command Rate 2T
XMP timings table CL-tRCD-tRP-tRAS-tRC-CR @ frequency (voltage)
XMP #1 6.0-6-6-18-32-2T @ 636 MHz (1.500 Volts)
XMP #2 7.0-7-7-21-37-2T @ 742 MHz (1.500 Volts)
XMP #3 8.0-8-8-24-42-2T @ 848 MHz (1.500 Volts)
XMP #4 9.0-9-9-27-47-2T @ 933 MHz (1.500 Volts)
XMP #5 10.0-9-9-27-47-2T @ 933 MHz (1.500 Volts)
DIMM # 1
SPD registers
00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F
00 93 13 0B 02 03 19 00 09 03 52 01 08 0C 00 34 00
10 6C 78 6C 30 6C 11 20 8C 00 05 3C 3C 00 F0 82 05
20 00 00 00 00 00 00 00 00 00 08 00 00 00 00 00 00
30 00 00 00 00 00 00 00 00 00 00 00 00 0F 11 01 01
40 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
50 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
60 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
70 00 00 00 00 00 85 9B 00 00 00 A4 13 34 49 B8 8F
80 42 4C 54 34 47 33 44 31 38 36 39 44 54 31 54 58
90 30 2E 01 00 80 2C 42 5A 41 48 39 57 4D 30 30 31
A0 FF 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
B0 0C 4A 01 13 01 0E 00 00 11 2A 0F 84 7C 00 84 84
C0 84 D2 21 8A B5 6D 00 C0 08 69 54 01 A4 69 00 00
D0 1C 00 26 00 00 00 00 00 00 00 00 00 00 00 00 00
E0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
F0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
DIMM # 2
SPD registers
00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F
00 93 13 0B 02 03 19 00 09 03 52 01 08 0C 00 34 00
10 6C 78 6C 30 6C 11 20 8C 00 05 3C 3C 00 F0 82 05
20 00 00 00 00 00 00 00 00 00 08 00 00 00 00 00 00
30 00 00 00 00 00 00 00 00 00 00 00 00 0F 11 01 01
40 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
50 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
60 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
70 00 00 00 00 00 85 9B 00 00 00 A0 19 CA 21 B8 8F
80 42 4C 54 34 47 33 44 31 38 36 39 44 54 31 54 58
90 30 2E 01 00 80 2C 42 5A 41 48 39 57 4D 30 30 31
A0 FF 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
B0 0C 4A 01 13 01 0E 00 00 11 2A 0F 84 7C 00 84 84
C0 84 D2 21 8A B5 6D 00 C0 08 69 54 01 A4 69 00 00
D0 1C 00 26 00 00 00 00 00 00 00 00 00 00 00 00 00
E0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
F0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
Monitoring
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Mainboard Model A88X-PRO (0x00000227 - 0x00A0C942)
DMI
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DMI BIOS
vendor American Megatrends Inc.
version 2603
date 03/10/2016
ROM size 8192 KB
DMI System Information
manufacturer System manufacturer
product System Product Name
version System Version
serial System Serial Number
UUID {6B64AB80-15C6-11E0-A92A-40167EAD028F}
SKU SKU
family To be filled by O.E.M.
DMI Baseboard
vendor ASUSTeK COMPUTER INC.
model A88X-PRO
revision Rev X.0x
serial 140525890700221
DMI System Enclosure
manufacturer Chassis Manufacture
chassis type Desktop
chassis serial Chassis Serial Number
1 Answer
It turns out slots B1/B2 are not working correctly. If I put both sticks into them, the comp doesn't boot. So it's a mobo or cpu defect. I'll look at the cpu pins when I have time, maybe they are damaged.
answered on Super User Feb 3, 2018 by 
warvariuc
warvariucUser contributions licensed under CC BY-SA 3.0