My motherboard is based on Intel Z68 chipset and supports up to 32GB RAM. I wanted to upgrade my current RAM (2*8GB + 2*4GB) to (2*8GB + 2*8GB), so I have 32GB in total.
Original (Working) 24 GB Configuration:
Northbridge Intel Ivy Bridge rev. 09
Southbridge Intel Z68 rev. B3
Memory Type DDR3
Memory Size 24 GBytes
Channels Dual
Memory Frequency 802.1 MHz (1:6)
CAS# latency (CL) 9.0
RAS# to CAS# delay (tRCD) 9
RAS# Precharge (tRP) 9
Cycle Time (tRAS) 27
Command Rate (CR) 2T
DIMMs #1 & #3
Memory type DDR3
Module format UDIMM
Manufacturer (ID) Kingston (7F980000000000000000)
Size 4096 MBytes
Max bandwidth PC3-10700 (667 MHz)
Number of banks 8
Nominal Voltage 1.50 Volts
EPP no
XMP yes
XMP revision 1.2
AMP no
JEDEC timings table CL-tRCD-tRP-tRAS-tRC @ frequency
JEDEC #1 6.0-6-6-17-23 @ 457 MHz
JEDEC #2 7.0-7-7-20-27 @ 533 MHz
JEDEC #3 8.0-8-8-22-30 @ 609 MHz
JEDEC #4 9.0-9-9-24-33 @ 666 MHz
XMP profile XMP-1600
Specification PC3-12800
Voltage level 1.650 Volts
Min Cycle time 1.250 ns (800 MHz)
Max CL 9.0
Min tRP 11.25 ns
Min tRCD 11.25 ns
Min tWR 15.00 ns
Min tRAS 33.75 ns
Min tRC 45.00 ns
Min tRFC 160.00 ns
Min tRTP 7.50 ns
Min tRRD 6.00 ns
XMP timings table CL-tRCD-tRP-tRAS-tRC-CR @ frequency (voltage)
XMP #1 6.0-6-6-18-24-n.a @ 533 MHz (1.650 Volts)
XMP #2 7.0-7-7-21-28-n.a @ 622 MHz (1.650 Volts)
XMP #3 8.0-8-8-24-32-n.a @ 711 MHz (1.650 Volts)
XMP #4 9.0-9-9-27-36-n.a @ 800 MHz (1.650 Volts)
DIMMs #2 & #4
Memory type DDR3
Module format UDIMM
Manufacturer (ID) Corsair (7F7F9E00000000000000)
Size 8192 MBytes
Max bandwidth PC3-10700 (667 MHz)
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 6.0-6-6-17-22 @ 457 MHz
JEDEC #2 7.0-7-7-20-26 @ 533 MHz
JEDEC #3 9.0-9-9-24-33 @ 666 MHz
XMP profile XMP-1600
Specification PC3-12800
Voltage level 1.500 Volts
Min Cycle time 1.250 ns (800 MHz)
Max CL 9.0
Min tRP 11.25 ns
Min tRCD 11.25 ns
Min tWR 15.00 ns
Min tRAS 30.00 ns
Min tRC 50.63 ns
Min tRFC 260.00 ns
Min tRTP 7.50 ns
Min tRRD 7.50 ns
Command Rate 2T
XMP timings table CL-tRCD-tRP-tRAS-tRC-CR @ frequency (voltage)
XMP #1 6.0-6-6-16-27-2T @ 533 MHz (1.500 Volts)
XMP #2 9.0-9-9-24-41-2T @ 800 MHz (1.500 Volts)
When I put the 2 new 8GB DDR3 SP DIMMs in place of the 2 old 4GB DIMMs, BIOS detects them and reports total memory correctly as 32GB. However, when I try booting up either Windows from the hard drive, or even the installation disk/USB flash drive, it appears to "hang". After running MemTest software, I realized that it is not hanging, but rather dramatically slows down (probably by a factor of 100!) at certain memory address ranges (i.e. MemTest slows down dramatically at certain places, but reports no errors).
The same thing happens regardless of:
- Where I insert the DIMMs (tried all kinds of combinations)
- What channel/rank interleaving settings I select in BIOS
- Whether I run at 1333MHz or at 1600MHz.
Not Working 32GB Configuration
Northbridge Intel Ivy Bridge rev. 09
Southbridge Intel Z68 rev. B3
Memory Type DDR3
Memory Size 32 GBytes
Channels Dual
Memory Frequency 802.1 MHz (1:6)
2 DIMMs in any 2 slots
Memory type DDR3
Module format UDIMM
Manufacturer (ID) Corsair (7F7F9E00000000000000)
Size 8192 MBytes
Max bandwidth PC3-10700 (667 MHz)
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 6.0-6-6-17-22 @ 457 MHz
JEDEC #2 7.0-7-7-20-26 @ 533 MHz
JEDEC #3 9.0-9-9-24-33 @ 666 MHz
XMP profile XMP-1600
Specification PC3-12800
Voltage level 1.500 Volts
Min Cycle time 1.250 ns (800 MHz)
Max CL 9.0
Min tRP 11.25 ns
Min tRCD 11.25 ns
Min tWR 15.00 ns
Min tRAS 30.00 ns
Min tRC 50.63 ns
Min tRFC 260.00 ns
Min tRTP 7.50 ns
Min tRRD 7.50 ns
Command Rate 2T
XMP timings table CL-tRCD-tRP-tRAS-tRC-CR @ frequency (voltage)
XMP #1 6.0-6-6-16-27-2T @ 533 MHz (1.500 Volts)
XMP #2 9.0-9-9-24-41-2T @ 800 MHz (1.500 Volts)
2 other DIMMs in any 2 remaining slots
Memory type DDR3
Module format UDIMM
Manufacturer (ID) Silicon Power (7F7F7F7F7F7FD3000000)
Size 8192 MBytes
Max bandwidth PC3-12800 (800 MHz)
Number of banks 8
Nominal Voltage 1.50 Volts
EPP no
XMP no
AMP no
JEDEC timings table CL-tRCD-tRP-tRAS-tRC @ frequency
JEDEC #1 6.0-6-6-16-22 @ 457 MHz
JEDEC #2 7.0-7-7-19-26 @ 533 MHz
JEDEC #3 8.0-8-8-22-30 @ 609 MHz
JEDEC #4 9.0-9-9-24-33 @ 685 MHz
JEDEC #5 10.0-10-10-27-37 @ 761 MHz
JEDEC #6 11.0-11-11-28-39 @ 800 MHz
What works, i.e. the speed is as it should be, and everything boots up is if I replace only 1 of the 4GB DIMMs with the new 8GB DIMM. Of course, with this arrangement I end up with 28GB and not 32GB that I hoped for.
Current ("Compromise") (Also Working) 28GB Configuration:
Northbridge Intel Ivy Bridge rev. 09
Southbridge Intel Z68 rev. B3
Memory Type DDR3
Memory Size 28 GBytes
Channels Dual
Memory Frequency 802.1 MHz (1:6)
CAS# latency (CL) 9.0
RAS# to CAS# delay (tRCD) 9
RAS# Precharge (tRP) 9
Cycle Time (tRAS) 24
Command Rate (CR) 2T
DIMMs #1 & #3
Memory type DDR3
Module format UDIMM
Manufacturer (ID) Corsair (7F7F9E00000000000000)
Size 8192 MBytes
Max bandwidth PC3-10700 (667 MHz)
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 6.0-6-6-17-22 @ 457 MHz
JEDEC #2 7.0-7-7-20-26 @ 533 MHz
JEDEC #3 9.0-9-9-24-33 @ 666 MHz
XMP profile XMP-1600
Specification PC3-12800
Voltage level 1.500 Volts
Min Cycle time 1.250 ns (800 MHz)
Max CL 9.0
Min tRP 11.25 ns
Min tRCD 11.25 ns
Min tWR 15.00 ns
Min tRAS 30.00 ns
Min tRC 50.63 ns
Min tRFC 260.00 ns
Min tRTP 7.50 ns
Min tRRD 7.50 ns
Command Rate 2T
XMP timings table CL-tRCD-tRP-tRAS-tRC-CR @ frequency (voltage)
XMP #1 6.0-6-6-16-27-2T @ 533 MHz (1.500 Volts)
XMP #2 9.0-9-9-24-41-2T @ 800 MHz (1.500 Volts)
DIMM #2
Memory type DDR3
Module format UDIMM
Manufacturer (ID) Kingston (7F980000000000000000)
Size 4096 MBytes
Max bandwidth PC3-10700 (667 MHz)
Number of banks 8
Nominal Voltage 1.50 Volts
EPP no
XMP yes
XMP revision 1.2
AMP no
JEDEC timings table CL-tRCD-tRP-tRAS-tRC @ frequency
JEDEC #1 6.0-6-6-17-23 @ 457 MHz
JEDEC #2 7.0-7-7-20-27 @ 533 MHz
JEDEC #3 8.0-8-8-22-30 @ 609 MHz
JEDEC #4 9.0-9-9-24-33 @ 666 MHz
XMP profile XMP-1600
Specification PC3-12800
Voltage level 1.650 Volts
Min Cycle time 1.250 ns (800 MHz)
Max CL 9.0
Min tRP 11.25 ns
Min tRCD 11.25 ns
Min tWR 15.00 ns
Min tRAS 33.75 ns
Min tRC 45.00 ns
Min tRFC 160.00 ns
Min tRTP 7.50 ns
Min tRRD 6.00 ns
XMP timings table CL-tRCD-tRP-tRAS-tRC-CR @ frequency (voltage)
XMP #1 6.0-6-6-18-24-n.a @ 533 MHz (1.650 Volts)
XMP #2 7.0-7-7-21-28-n.a @ 622 MHz (1.650 Volts)
XMP #3 8.0-8-8-24-32-n.a @ 711 MHz (1.650 Volts)
XMP #4 9.0-9-9-27-36-n.a @ 800 MHz (1.650 Volts)
DIMM #4
Memory type DDR3
Module format UDIMM
Manufacturer (ID) Silicon Power (7F7F7F7F7F7FD3000000)
Size 8192 MBytes
Max bandwidth PC3-12800 (800 MHz)
Number of banks 8
Nominal Voltage 1.50 Volts
EPP no
XMP no
AMP no
JEDEC timings table CL-tRCD-tRP-tRAS-tRC @ frequency
JEDEC #1 6.0-6-6-16-22 @ 457 MHz
JEDEC #2 7.0-7-7-19-26 @ 533 MHz
JEDEC #3 8.0-8-8-22-30 @ 609 MHz
JEDEC #4 9.0-9-9-24-33 @ 685 MHz
JEDEC #5 10.0-10-10-27-37 @ 761 MHz
JEDEC #6 11.0-11-11-28-39 @ 800 MHz
So, my question is why am I experiencing ~100 time slow down at certain addresses if I replace 4GB DIMM #2 from the Current Configuration above with the 8GB DIMM - identical one as DIMM #4 from the Current Configuration above?