RMA Corsair TwinX XMS 4400C25PT DDR550

[ReelFiles]

Well, I've had this RAM for over a year now, but was never able to run it 1:1 (275MHz) with my CPU. No luck at any voltage or with any advanced DRAM settings. I've had several pages long threads, here and at the Corsair support forum, to no avail. Even RAM Guy wasn't much help, except for him telling me that they test this RAM at 2T, which isn't mentioned anywhere on the specifcation sheet or on the Corsair product site.

Frankly I am very disappointed with this RAM, and I was wondering if I can still RMA these sticks and get replacements from Corsair, now that DDR RAM is getting phased out. Will I get different RAM or does Corsair stockpile different sticks for RMA reasons?

 

I know that we have a Corsair rep member now, hopefully you can help me Yellowbeard.

[ReelFiles]

I have run these modules from 2.6vup to 3v, with fan cooling. I've tried relaxing the timings, tightening them, tried switching slots. They just will not run at 275MHz SuperPi or Prime95 stable, but memtest86 never finds any errors with either stick or both together.

 

 

I am willing to try to get these to work, so if anybody has any ideas, I am open to suggestions.

[Yellowbeard]

Got your PM. First thing I would suggest is testing each module individually with www.memtest.org

 

They should do fine at 2.7v to 2.8v range. Also, set the RAM timings manually 2.5,3,3,7. I have not had a DFI to play with (yet!) so I'll need to brush up on their bios tweaks. I'll have a look here and with Google to see what others running TCCD based memory are doing to make it scream.

 

Also, I see you have an Opty so I can assume it will run more than 275mhz. Have you tried it with downclock on the memory just to verify that the CPU will run 275mhz+?

[ReelFiles]

Thank you for your quick response.

 

I have to run the memory at 2.93v minimum to get anything above 250MHz stable. I ran the default tests in memtest86 for 50 passes error free, then

I ran dual memtest for windows with 450Mb allocated for each instance, they passed 5000% error free. The CPU passes 12 hours of dualPrime95 up to 285MHz x10, then heat becomes the limiting factor. At those speeds, I get random shutdowns, BSODs and neither SuperPi or dual Prime95 will pass (if it even makes it into Windows).

If I drop the memory divider to 166 and change to CAS 3, it works fine.

 

I had a different CPU when I first got this RAM, and I had the same problem with this RAM then, but I figured it was the CPU. I did several clean installs since, so software can be ruled out, I am at the end of my rope.

 

Here are my advanced DRAM settings at this moment;

 

FSB Bus Frequency - 275
LDT/FSB Frequency Ration - 3x
CPU/FSB Frequency Ratio - 7x [B]<---lowered for testing purposes[/B]
PCI eXpress Frequency - 100Mhz

CPU VID StartUp Value - Startup

CPU VID Control - 1.45v
CPU VID Special Control - AUTO
LDT Voltage Control - 1.30v
Chip Set Voltage Control - 1.60v
DRAM Voltage Control - 2.9v +.03 = 2.93v

DRAM Configuration Settings:

DRAM Frequency Set - 166 
Command Per Clock (CPC) - Disable
CAS Latency Control (Tcl) - 3
RAS# to CAS# delay (Trcd) - 04 Bus Clocks
Min RAS# active time (Tras) - 08 Bus Clocks
Row precharge time (Trp) - 04 Bus Clocks
Row Cycle time (Trc) - 12 Bus Clocks
Row refresh cyc time (Trfc) - 19 Bus Clocks
Row to Row delay (Trrd) - 03 Bus Clocks
Write recovery time (Twr) - 02 Bus Clocks
Write to Read delay (Twtr) - 02 Bus Clocks
Read to Write delay (Trwt) - 04 Bus Clocks
Refresh Period (Tref) - 2560 Cycles
Write CAS Latency (Twcl) - 05 Bus Clocks
DRAM Bank Interleave - Enabled

DQS Skew Control - Auto
DQS Skew Value - 0
DRAM Drive Strength - Weak4
DRAM Data Drive Strength - Level 2
Max Async Latency - 9.0 Nano Seconds
DRAM Response Time - Fast
Read Preamble Time - 6.0 Nano Seconds
IdleCycle Limit - 256 Cycles
Dynamic Counter - Disable
R/W Queue Bypass - 16 x
Bypass Max - 04 x
32 Byte Granularity - Disable(4 Bursts)

 

Do you still want me to test the sticks at 2.5,3,3,7 / 2.75v?

I thought they were rated for 2T 2.5 4 4 8 (RAM Guy at Corsair support forum said that they test with 2.8v at 2T)

Thanks in advance,

-Steve

[Yellowbeard]

No, the timings RAM GUY gave were correct, I misquoted there. Let me have a look around and see if there is some DFI specific setting we are missing here for the TCCD memory. Thanks for your patience.

[ReelFiles]

Sure, take your time. In the meantime, I will update my bios to Tony's 4/06, I'll let you know if it helps.

Thank you.

[Technohydra]

You might also try setting your tREF to something closer to 1800 or 1900.

 

I think the exact number I got was 1818, but I know that's not a selectable setting.

[ReelFiles]

I changed tRef to 1560, according to this theory, 2560 is not the optimal value.

 

1 / f = t

 

1 / 275 = ~.0036

 

0.0036 x 1000 = 3.6ns

 

1560 x 3.6 = 5616 = ~5.6 microseconds

 

 

Clock cycles = Refresh rate / t

 

Clock cycles = 5.6 / (1/275) = ~1555

 

Thanks for pointing that out, but it BSOD before even getting to the desktop

 

I've actually tried that before, but I gave it another shot for the hell of it. Updating the bios didn't have any positive effect

[Yellowbeard]

You have been extremely patient. Between my admittedly thin DFI knowledge and the experts here this memory has not performed to spec yet. I have no idea if it is the memory. So, if you think it IS the memory and would like to try a new pair of modules, let's start an RMA case at our TSX (Tech Support Express).

 

Keep in mind none of the people in TSX will see this before Monday but, I hope this is the solution. Please tell them you were referred by Yellowbeard thru the DFI forums.

 

http://tsxpress.corsairmemory.com/

[ReelFiles]

Ok, sounds good to me. Thank you.

-Steve

 

Edit:

 

When I went to the Tech express site (here), my RAM modules weren't on the list:

[ReelFiles]

I sent a message to Corsair from the link on that page last night, hopefully I will get a response in a timely manner.

[Yellowbeard]

It will still likely be Monday before the TSX guys see it. On that drop down list, there is an option for NOT LISTED. Choose that and go ahead thru the process.