Asus Z77 Sabertooth only seeing half of ram

slats

[H]ard|Gawd
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Oct 30, 2000
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Been running this setup for some time now without issues. I am using latest official bios and the motherboard is only seeing half of the 16gb ram installed. I have narrowed it down to the DIMM A2 and DIMM B1 (the two middle slots). All sticks work, just not in those slots. I have pulled CPU to reseat and check for bent pins but they all look factory new. The memory is Ballistix tracer 1866 XMP 1.5v memory and even at 1333 it will not recognize all 16 gigs. The UFEI bios shows only 8 gig and windows shows the same, funny thing is CPU-Z recognizes all 16 gigs. I am to the point of attempting to RMA or ditching it all together. I've seen many other Asus Z77's experience this issue and most are resolved either by fixing bent socket PINS, ground shorts and by RMA'ing the board. If anyone has any additional insight on this issue I would appreciate it. With work, soccer, family etc I have not had much time to deal with it. I mean it works fine with only 8 gigs but it is annoying.

Thanks, Todd
 
Mod please feel free to move this to the Intel mobo section since I overlooked that fact when posting. Thanks.
 
Sometimes it can be caused by too much CPU heatsink pressure, have you tried loosening it or maybe a different heatsink? You were on the right path first checking the socket pins though because the memory controller is on the processor and with memory not being detected that's often the cause. Another thing you could try is downclocking the memory to 1333mhz and see if it all recognizes, or increase the VCIO voltage but I don't think those will necessarily help.
 
I'm using a H100 which just snugs up. I backed it off yesterday and tightened it just enough but no improvement. The thing is if they are compressed from too much pressure that could be a worse issue that having a few bent pins. Thanks, Todd
 
I had the same thing happen on another model Asus board about a year ago. I have been building computers for over 10yrs and never had a CPU / motherboard mating issue until then. I like you tried everything and finally RMA'ed the board. As it turned out there were a couple of bent pins on the motherboard and both the vendor and Asus refused an exchange, so I had to eat the cost of a new motherboard. I hope this is not your issue but keep it in mind if you can't find another reason.
 
I just got the board back from RMA and it continues to suffer the same issues. The problem/repair on the service shipping lpack list under the FROM: section reads "PTSI_CHANNEL2". All dimm sticks run individually in each slot and is recognize as 4gb. The 2nd dimm from CPU will not recognize any ram if either of the remaining slots are populated but recognizes fine if it is the only one in the motherboard. This is really frustrating and am beginning to wonder if the service center even bothered to check the board with each dimm slot populated.


I would appreciate if other forum members could share some thoughts on this.
 
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Completed an advance RMA for a new board, it works as it should.
 
Definitely an interesting problem. Glad you got it taken care of. In most cases if its not bent pins or too much pressure on the CPU it's probably a bad board. I had the same issue with a Z87 maximus hero. Thankfully Microcenter took it back and exchanged it for a new one.
 
Well the RMA lasted for 2.5 years, it has now failed again. There doesn't seem to be anything out there compelling enough to make me want to upgrade. I may pursue a warranty replacement, I'm unsure.
 
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