CPU/Mobo 800 Mhz RAM coming as 667

[adi_vastava]

Hi,

I have 2 DDR2, both 800 Mhz Ram and when I insert them one at a time, bios recognize them both as 800 Mhz. But when both inserted together it reports them to 667 Mhz.

Obviously its because of some mismatch, but I am not sure what is that. following is the data from CPUz.

DIMM # 1
SMBus address 0x50
Memory type DDR2
Module format Regular UDIMM
Manufacturer (ID) Transcend Information (7F4F000000000000)
Size 2048 MBytes
Max bandwidth PC2-6400 (400 MHz)
Part number JM800QLU-2G
Serial number 0007BF3D
Manufacturing date Week 14/Year 08
Number of banks 2
Data width 64 bits
Correction None
Nominal Voltage 1.80 Volts
EPP no
XMP no
JEDEC timings table CL-tRCD-tRP-tRAS-tRC @ frequency
JEDEC #1 3.0-3-3-9-12 @ 200 MHz
JEDEC #2 4.0-4-4-12-16 @ 266 MHz
JEDEC #3 5.0-5-5-18-23 @ 400 MHz

DIMM # 2
SMBus address 0x52
Memory type DDR2
Module format Regular UDIMM
Manufacturer (ID) Transcend Information (7F4F000000000000)
Size 2048 MBytes
Max bandwidth PC2-6400 (400 MHz)
Part number JM800QLU-2G
Serial number 0007F2C5
Manufacturing date Week 08/Year 09
Number of banks 2
Data width 64 bits
Correction None
Nominal Voltage 1.80 Volts
EPP no
XMP no
JEDEC timings table CL-tRCD-tRP-tRAS-tRC @ frequency
JEDEC #1 4.0-4-4-12-16 @ 266 MHz
JEDEC #2 5.0-5-5-15-20 @ 333 MHz
JEDEC #3 6.0-6-6-18-24 @ 400 MHz
All I can notice is different levels of JEDEC timings. any comment/suggestions.

Additionally 667 or 800 Mhz will it really have some significant impact in speed?

Thanks
Aditya

 

[madnav]

both modules have different latency.

not sure if the module in DIMM 1 would support cas6..

try setting latency = JEDEC#3 of DIMM2 in bios.