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Problems with 4x2 GB Corsair XMS2 (PC6400)...


a15995

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Hello!

 

I just bought 4 sticks of 2GB XMS2 memory and have had problems ever since. I have isolated the problem to the ram since I have no problems with my old 800 Mhz noname ram of 2x1GB.

 

My motherboard supports 8 GB of PC6400 ram but still I get BSOD when getting to desktop if the computer will even post. The BSODs cover all from "Memory Management", "System Halted" and the ever so wide "IRQL Not Less or Equal"-error.

 

I have overclocked my CPU from 2.4GHZ to 3.0Ghz by increasing the FSB from 266Mhz to 333Mhz without messing with the BIOS or voltages. The system has been stabile for several months and still is with the noname memory inside.

 

My noname RAM handled this (the BIOS handled it) by changing the FSB:DRAM ratio from 2:3 to 5:6 which I was expecting the XMS2 to do also. Apparently the XMS2 does not like this ratio...

 

I read somewhere else that other users had no problems running XMS2 with the 5:6 ratio (on a Dell computer) so I'm a little lost here...

 

I have tested with all sticks in there and only two sticks and still have problems. The system is sometimes stabile until I launch a web browser etc. - so in fact very unstabile.

 

Any suggestions as to what is going on? Any solutions? Should I really go back to stock clock on the CPU and will that even help? Is the ram faulty (all of the sticks)?

 

Hope someone has been there before and has some tricks...

 

Thanks!

/Søren

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I tried putting 2 sticks of the XMS2 in combination with my noname ram (Nanya) and that seems to be stabile but the timings seems a bit strange (only two tables for the XMS2 - 270Mhz(?!) and 400Mhz) and to me it looks "slow" but can someone please comment on why this works and if it is a good combo?

 

The tRC is 22 (XMS2) and 23 (Nanya) which seems off and tRFC is 52 clocks which seems kind of high/not optimal?

 

From CPUID:

 

DIMM # 1

SMBus address 0x50

Memory type DDR2

Module format Regular UDIMM

Manufacturer (ID) Nanya Technology (7F7F7F0B00000000)

Size 1024 MBytes

Max bandwidth PC2-6400 (400 MHz)

Part number M2Y1G64TU8HB4B-25C

Serial number 2802F411

Manufacturing date Week 26/Year 07

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 0x51

Memory type DDR2

Module format Regular UDIMM

Manufacturer (ID) Corsair (7F7F9E0000000000)

Size 2048 MBytes

Max bandwidth PC2-6400 (400 MHz)

Part number CM2X2048-6400C5

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 4.0-4-4-13-15 @ 270 MHz

JEDEC #2 5.0-5-5-18-22 @ 400 MHz

 

DIMM # 3

SMBus address 0x52

Memory type DDR2

Module format Regular UDIMM

Manufacturer (ID) Nanya Technology (7F7F7F0B00000000)

Size 1024 MBytes

Max bandwidth PC2-6400 (400 MHz)

Part number M2Y1G64TU8HB4B-25C

Serial number A402F411

Manufacturing date Week 26/Year 07

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 # 4

SMBus address 0x53

Memory type DDR2

Module format Regular UDIMM

Manufacturer (ID) Corsair (7F7F9E0000000000)

Size 2048 MBytes

Max bandwidth PC2-6400 (400 MHz)

Part number CM2X2048-6400C5

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 4.0-4-4-13-15 @ 270 MHz

JEDEC #2 5.0-5-5-18-22 @ 400 MHz

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Mixing memory would not be suggested but you are welcome to try it and I would use CPU-Z and look under the Memory tab to what the memory is running at. I would also suggest running them at DDR667 as well.

 

Well I don't really have a choice do I? The XMS2 won't run at all unless coupled with the noname memory... I sure would rather run all 8GB of XMS2 on its own but that causes BSOD.

 

So my question is, why does XMS2 work coupled with cheap memory? It is as if the cheap memory tells the BIOS what to do and the Corsair memory just can't say "I want to run 5:6"...

 

Anyway, the memory is running 400 Mhz (800 Mhz) in CPU-Z and SiSoft Sandra reports 5.66GB/s of bandwith. I guess that's not bad.

 

But again, would like to run XMS2 all the way - maybe I need 2x1GB + 2x2GB making a total of 6GB for it to work...?

 

Thanks,

Søren

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In order to run two sets you would need to set the memory frequency manually to DDR667 and since this is an OEM system I do not think you have that option. So the only choice is to just run one set.

 

OK I kind of suspected this but why can I run 2 different brands on 800 Mhz? Is it because it is 1+2+1+2 GB sticks (in that order)? If so, why can't I just get 2x1GB of XMS2 and experience the same magic?

 

6GB would be fine but since the 2x1 noname are borrowed I need to get 2x1GB sticks somewhere else with the same properties - hopefully XMS2...

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  • Corsair Employees
It is a loading issue on the memory controller most likely, the 1.0 Gig modules are most likely single rank and all 2.0 Gig modules are double rank and there are 20 loads per rank with UN-buffered memory on the memory controller.
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It is a loading issue on the memory controller most likely, the 1.0 Gig modules are most likely single rank and all 2.0 Gig modules are double rank and there are 20 loads per rank with UN-buffered memory on the memory controller.

 

Errrr, ok... What does that mean? The 1GB module is in the first DIMM/SMBUS so does that mean that the first module "decides" on the behaviour of the rest or?

 

Does it mean that because XMS2 is a bit "odd" compared to a standard computer setup (that is a setup with no voltage mods) I won't even have succes with a 1GB XMS2 in the first slot? Or does it mean the opposite?

 

I appreciate your thoughts here, thanks!

 

/Søren

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  • Corsair Employees

I don't know how else to explain it and NO all or memory modules are built to the JEDEC standard. With the exception of the Over Clocked Parts we manufacture, but they are still built to JEDEC standards. Just they will use an XMP or EPP Profile for the performance settings.

I would suggest doing some research on how memory works if you really want to understand memory.

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Here Soren, this is a pretty good explanation and may provide a little light on it for you. :)

 

http://www.hardwaresecrets.com/article/167

 

Thanks for your input but I get that. I'm just curious as to how I get a stabile system by mixing the ram instead of an unstabile system with same ram.

 

Originally the system was equipped with 333Mhz ram from Samsung and Hyundai (I think). All slots full of 1,8v DDR2 memory. The mobo takes 400Mhz PC2-6400 ram - but how many sticks does it in fact support?

 

So I have come to realize that 8GB won't work, so I'll be buying two sticks of Corsair XMS2 1GB to see if 6GB will work better. I'm just a little uncertain since the Corsair won't work with 2x2GB sticks.

 

Maybe it's just better to buy 6GB of Kingston valueram which have normal JEDEC timings since I'm not going to or am able to put more voltage to the ram.

 

I mean why would HP choose to put different brands of ram in there in the first place and with different configuration (0,5GB+1GB+0,5GB+1GB)?

 

Thanks,

Søren

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