875P NEO FIS2R with Corsair TwinX1024-4000

Question

Hi there,
My first post, not sure if it should be here or in the Intel P4 based board forum, but we'll start here.
System posted in signature (hopefully  )
I've tried to read as much as possible on the compatibility issues, but cannot find anyone who has experienced quite the same thing.
The Problem:-
I cannot get my Corsair TwinX1024-4000 memory to run at its rated 500 MHz.  
The main reason for this appears to be that no matter what BIOS settings I use the CAS # Latency will not go above 2.5 cycles. Consequentially, my memory will not clock above 230 MHz (DDR 460 MHz).
I currently have the BIOS set to manually force 3-4-4-8 + 8 burst, but CPU-Z still reports 2.5-4-4-8. DOT is off, Performance mode is slow. Memory Voltage is 2.75V.
I appreciate that the SPD configuration of these is PC3200 and therefore AIDA32 reports:-
Quote
Memory Module Properties   
Module Name   Corsair CMX512-3200C2
Serial Number   None
Module Size   512 MB (2 rows, 4 banks)
Module Type   Unbuffered
Memory Type   DDR SDRAM
Memory Speed   PC3200 (200 MHz)
Module Width   64 bit
Module Voltage   SSTL 2.5
Error Detection Method   None
Refresh Rate   Reduced (7.8 us), Self-Refresh
Highest CAS Latency   2.5 (5.0 ns @ 200 MHz)
2nd Highest CAS Latency   2.0 (6.0 ns @ 166 MHz)
Memory Module Features   
Early RAS# Precharge   Not Supported
Auto-Precharge   Not Supported
Precharge All   Not Supported
Write1/Read Burst   Not Supported
Buffered Address/Control Inputs   Not Supported
Registered Address/Control Inputs   Not Supported
On-Card PLL (Clock)   Not Supported
Buffered DQMB Inputs   Not Supported
Registered DQMB Inputs   Not Supported
Differential Clock Input   Supported
Redundant Row Address   Not Supported
Memory Module Manufacturer   
Company Name   Corsair Memory, Inc.
Product Information   http://www.corsairmicro.com/main/products.htm
I know that some people have reported issues with loading all 4 channels with the 875, but I have tested with 1, 2, and 4 modules and it makes no difference to this issue. The only thing I see is a memory bandwidth change (Sandra 2004 - single channel approx. 4000 Mb/s, Dual Channel approx. 5300 Mb/s, Quad Channel approx. 5150 Mb/s)
So cutting to the chase, why can I not force CAS # Latency = 3???  
I have recently tried the 1.9beta   , but it would not post past "Checking NVRAM" for me, so have returned to pukker 1.9.
I have 4 other MSI   based systems that work a treat, so I'd hate to have to go buy an ASUS   to get my memory to work.
Any help will be greatly appreciated.
Best Regards,
Ed!

Answer 1

I agree that the memory "optimization" attempt by MSI for the 875 causes a great deal of suffering for all of us who use the MOBO. But I encourage you to bide your time a little longer, before pumping another couple hundred bucks into a second board. I have read an almost unimaginable (and probably unhealthy) amount of data about the Memory Substructure of the 875 MOBOS and their various compatibility quirks w/ different RAM. And I spend damn-near as much time in the other MOBO makers' forums as in this one! All of this observation/research plus the lessons I have absorbed at the feet of "THE REILLY875" , have convinced me that all of the boards have serious potential fubars depending on a vast number of variables. If you were looking to buy your 1st 875 MOBO, I think that ASUS or ABIT would be the best/safest/highest OC performance choices. But as you already have the MSI, I think that the "smart money" favors sitting tight for another BIOS update and/or new RAM models which might be designed w/ the various memory compatibility problems in mind. Besides, it is possible to get a mid-range OC w/ the current MSI 875, you just need really good 3500, or 4000+ RAM. I'd hate to see you switch boards only to encounter one of the documented problems w/ the other 875 MOBOS, followed by a (I'm trying to be veeeeery positive here!)  fixed/optimized BIOS from MSI. Whichever you chose, brother, I'm happy to help any time!
                  damon69