2-year stable system now boot-looping

I have been running a 4x4GB matched set on my Asus board for over 2 years with rock-solid performance. Now it boot loops on start up and I cannot even get into the BIOS. I removed 2 sticks of memory and it then runs fine. Here's what I know:

 

Running either pair of memory works fine. In that configuration, MemTest+ reports no errors on either pair after running all night.

 

Running both pairs causes the boot loop.

 

The SAME situation occurs when I try this memory set on another Asus board that also has been running fine. Either pair works on that board, but the two pairs together cause a boot loop on startup.

 

Voltages and timings in the BIOS are set to defaults. With one pair installed, CPU voltage shows as 1.04, DIMM voltage shows as set to 1.5.

 

What to do? Any help appreciated!

if both pairs pass memtest but 4 sticks causes looping, it sounds more like the memory controller on the CPU.

have you changed anything recently that may have bumped the heatsink?

i understand it does the same on another system though.

try removing the battery for like 10 minutes and see if all 4 sticks will at least let you into the bios to fix the date and boot sequence.

if they were a 16g matched set you can apply for an RMA but its odd that pairs pass memtest overnight.

i just wanted to see you check the basics befor playing with voltages or RMA.

good luck, let us know.

I tried removing the CMOS battery to reset the BIOS and discovered it was nearly dead. Putting in a new battery, however, did not solve the memory rebooting problem. I can get the system up and running with any 2 or 3 sticks out of the original 4x4G matched set. And they still all memtest+ OK.

 

I also considered the possibility of a memory controller issue or something on the mainboard (ASUS P8Z77-V Pro). But I find it hard to believe that because the problem also occurs when I put the 4 sticks into a completely different mainboard. When the 4 sticks are in together, the mem-error LED on the mainboard lights up as soon as power is applied. The boot fails after about two seconds and then attempts to reboot a few seconds later.

 

Is it possible that something happened to the 4x4G set so that they are no longer "matched"?

Corsair customer service issued a RMA for the memory based on my description of the problem. I FedExed the memory to them and they shipped me a replacement direct from Taiwan. The whole process only took a week. The new memory works great. Thanks, Corsair!

that's great news!

thanks for letting us know the result!!