Corsair VDimm Problems (6400 RAM)

[imported_Buckster]

I've been rather disappointed with the matched 2 gig pair (2x1Gig) of this RAM - its standard 6400 stuff, TwinX, CAS5 version.

I've never known RAM NOT to like extra Vdimm before ... which seems to me an odd behaviour ...

At stock SPD speed 800 MHz, 5-5-5-15 - 1.9 VDimm is fine, Orthos stable for hours, but if I increase the Vdimm to 1.95V, won't last more than 3 minutes in Orthos, and above 1.95V, 2.0V, 2.05V, or 2.1V - won't last for more than 40 seconds ....

if I overclock slightly - up to 840MHz, 5-5-5-15 or even 18, 1.9V Vdimm is not enough, but 1.95V then suddenly becomes OK, but again, anything over that is stable for less than 3 minutes. Above 845 - at any voltage, completely unstable - but will boot.

I know I can't expect memory to overclock, but I've never known RAM not to like extra voltage, not enough one would of course expect it to be unstable.

Cooling is not a problem, case has 3 120mm fans, and case is large and uncluttered.

I've done some further tests - to see if I could work out what is going on.

If I set memory to 800 MHz, SPD settings, VDimm to 2.1V - then run Mem Test in dos - it doesn't get past test 5 without errors, test 5 gives 370 errors itself.

If I set memory to same settings, but VDimm to 1.9V - Mem Test passes fine.

I thought these modules were meant to take 2.1V without any problems ? Any idea to why it can't ?

thanks, Mark.

 

[myocardia]

Assuming your psu isn't running out of power on the 3.3v rail, it sounds to me like you should RMA your RAM.

 

[imported_Buckster]

myocardia - PSU should be OK - its a Tagan 700W PSU

RMA does seem the likely route I think

Mark.

 

[execine]

i have read that this 6400 series is not really good for overcloking much.. mine does the same, if i bump up the voltage, i get errors.. i don't think that it is also faulty...

 

[imported_Buckster]

thanks - you're probably right - they probably are just really poor overclockers/don't like voltage. I would have expected 10% overclock - but nevermind

you read some people here with same RAM managing DDR 1000 @ CAS 5 ! they must just be really lucky I suppose.

Mark.

 

[cmdrdredd]

Originally posted by: Buckster
thanks - you're probably right - they probably are just really poor overclockers/don't like voltage. I would have expected 10% overclock - but nevermind

you read some people here with same RAM managing DDR 1000 @ CAS 5 ! they must just be really lucky I suppose.

Mark.

It's not luck so much as setting everything manually including MB voltages.

 

[imported_Buckster]

ok - thanks - could you give me a steer to some reasonable mobo voltages please - I'm worried about blowing the mobo up.

Mark.

 

[stm69]

Your experience mirrors mine. At the default voltage, memtest will run fine for a few hours. But if I up the voltage, errors creep in, 10-20 or so, not 370 like you said. I'm using my sticks in a c2d setup, but only @ 400 mhz fsb, so it's running at rated. But I'm unable to bump any higher as a result.

 

[imported_Buckster]

I had the answer from the Corsair guy - and it all begins to make sense now ....

these are the modules that can be used on the 6400 C5 stuff

CM2X512A-6400 XMS6405v4.1 0633067-1 = PROMOS 800MHZ, CL5, 0.09u 64Mx8 ETT
CM2X1024-6400 XMS6405v5.1 0634287-2 = PROMOS 667MHZ, CL5, 0.09u 64Mx8 ETT
CM2X1024-6400 XMS6405v5.1 0631252-2 = PROMOS 667MHZ, CL5, 0.09u 64Mx8 ETT
CM2X1024-6400 XMS6405v5.1 0631252-9 = PROMOS 667MHZ, CL5, 0.09u 64Mx8 ETT
CM2X1024-6400PRO XMS6405v1.1 0610028-1 = Micron, 64Mx8, DDR2-667, CL5, Die Rev D
CM2X1024-6400 XMS6405v5.1 0633171-6 = PROMOS 667MHZ, CL5, 0.09u 64Mx8 ETT
CM2X1024-6400 XMS6405v5.1 0629230-7 = PROMOS 667MHZ, CL5, 0.09u 64Mx8 ETT
CM1024X2-6400 XMS6405 v4.1 0626413-3 = Infineon AENEON, Die Rev B, 64M X 8 Rev B
CM2X1024-6400PRO XMS6405v3.1 0609115-2 = Infineon AENEON, Die Rev B, 64M X 8 Rev B
CM2X1024-6400 XMS6405v4.1 0609102-1 = Infineon AENEON, Die Rev B, 64M X 8 Rev B
CM2X1024-6400, XMS6405 v1.4, 0606096-2 = Micron, 64Mx8, DDR2-667, CL5, Die Rev D
CM2X512A-6400 XMS6405v1.1 0531093-0 = Micron, 64Mx8,2-533, CL4, MT47H64M8FT-37E Die Rev A
CM2X512A-6400 XMS6405V3.1 0609062-1 = Infineon AENEON, Die Rev B, 64M X 8 Rev B
CM2X1024-6400PRO XMS6405v1.3 0610028-1 = Micron, 64Mx8, DDR2-667, CL5, Die Rev D
CM2X512A-6400 XMS6405v3.1 0628012-2 = Infineon 64Mx8, DDR2, AENEON, Die Rev B (90nm)
CM2X512A-6400 XMS6405v4.1 0631250-9 = PROMOS 0.09u 64Mx8 ETT

mine is this one ... CM2X1024-6400 XMS6405v5.1 0633171-6

I've been told that most of them apart from the Micron, have voltage regulators on them, and if they get say over 1.95V or 2.0V say, it will regulate it back down to 1.8-1.9V.

Just shows how much potential variation there is - just from one part - and how some people can get DDR 1000 out of them and others not - its obviously some of the module manufacturers are better than others - a bit annoying when we all pay the same price.

Mark.

 

[Clones123]

http://www.houseofhelp.com/forums/showthread.php?t=52351

XMS2 6400.......is tested at 800Mhz with timings of 5-5-5-15 @ 1.9 V
XMS2 6400C4...is tested at 800Mhz with timings of 4-4-4-12 @ 2.1 V
XMS2 6400C3...is tested at 800Mhz with timings of 3-4-3-9 @ 2.1 V

I have to wonder though - how often can one get 6400C4 timings out of regular 6400 just by increasing the vdimm to 2.1 V ?