CMSX4GX3M1A1600C9 with different timings

[murph70]

Hi,

 

I just bought two CMSX4GX3M1A1600C9 modules for my Asus N53sv from Amazon.

I would have just bought the kit with two of these 4gb modules but they were out of stock and I'd already been waiting a few weeks for them to come in with no word of when they would appear.

I went for the next best thing and just ordered two of the 4gb Vengeance 12800 SODIMMS.

Now that I've installed them cpu-z is reporting one as PC3-12800H (800 MHz) and the other as PC3-12800 (800 MHz) with different JEDEC timings for each.

Here is the relevant part of the cpuz report;

 

DIMM # 1

SMBus address 0x50

Memory type DDR3

Module format SO-DIMM

Manufacturer (ID) Corsair (7F7F9E0000000000)

Size 4096 MBytes

Max bandwidth PC3-12800H (800 MHz)

Part number CMSX4GX3M1A1600C9

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 6.0-6-6-16-26 @ 533 MHz

JEDEC #2 7.0-7-7-19-30 @ 622 MHz

JEDEC #3 9.0-9-9-24-39 @ 800 MHz

 

 

 

 

DIMM # 2

SMBus address 0x52

Memory type DDR3

Module format SO-DIMM

Manufacturer (ID) Corsair (7F7F9E0000000000)

Size 4096 MBytes

Max bandwidth PC3-12800 (800 MHz)

Part number CMSX4GX3M1A1600C9

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 6.0-6-6-17-27 @ 545 MHz

JEDEC #2 7.0-7-7-20-31 @ 636 MHz

JEDEC #3 9.0-9-9-25-40 @ 818 MHz

JEDEC #4 11.0-11-11-30-49 @ 1000 MHz

 

 

Is this normal for two modules with the same part number? Would I be better off returning them to see if I can obtain two identical modules?

[peanutz94]

Not always normal, but entirely possible. If the modules were made from different chips they could very well have different timings. This is one of the cases where buying a matched kit would have been ideal. Corsair does not suggest or support mixing memory ...even if it is the same exact part number because of these types of issues.

 

However if the machine is stable I wouldn't worry too much about it. The BIOS should compensate even though the SPD is different.

My wife has the same LP and for the most part the BIOS is locked down not allowing you to adjust them manually.

But if you would happen to start having memory related issues, then i would return them for a matched 8 gig kit.

[murph70]

Thanks for answering.

Yes the BIOS doesn't allow you to alter anything to do with the memory so it's running as pc3-10600 at 666MHz. I thought it might have run at 800MHz but it seems the BIOS doesn't enable this.

I thought it odd that the second dimm doesn't have a JEDEC setting programmed for 800MHz and the two have no programmed settings in common at all.