My ASUS ROG STRIX Z370-G Gaming motherboard refuses to POST when I install both of my previously working RAM sticks. Startup produces one long beep followed by two short beeps in a loop, and the motherboard's orange DRAM LED stays lit. Windows does not load.
I tested each stick separately in both the A2 and B2 slots, and every individual combination boots normally. The failure only happens when both sticks are installed together, whether I use A2 + B2 or A1 + B1. I have reseated the modules several times and reset the CMOS by removing and reinstalling the battery. Loading the BIOS optimized defaults with one stick installed also did not solve the problem.
What should I test next? Could this be caused by incompatible settings, a problem with dual-channel operation, or an issue elsewhere in the memory system even though both sticks and slots work individually?
3 Answers
Run a proper MemTest86 or MemTest86+ test with XMP disabled and the BIOS at default settings. Test each stick separately in each slot, then compare the results and the memory information reported by the test. You do not necessarily need an extremely long test for every combination at first, but a longer pass is useful if any result looks suspicious. This can reveal marginal memory errors that do not show up during a normal boot and can help distinguish a bad module from a configuration or memory-controller problem.
Make sure the system is using completely default memory settings before testing both modules. With one stick installed, enter the BIOS, load optimized defaults, save, power the machine off, and then install the second stick. Use the recommended paired slots, normally A2 and B2. If that still fails, try the same reset process with A1 and B1. Also verify that the two modules are actually a matched kit with compatible specifications; two sticks can each work alone but fail together because of different timings, voltage requirements, ranks, or an XMP profile.
I already tried A1 + B1 and A2 + B2, and I loaded the optimized defaults with one stick installed before adding the other. Unfortunately the DRAM light and beeping returned. I may need to check whether the modules are truly a matched kit and test with XMP definitely disabled.
If both modules pass individually and the slots work individually, the remaining possibilities include a compatibility problem between the modules, an unstable memory setting, or an issue with the CPU’s integrated memory controller or motherboard socket contacts. Inspect the CPU socket carefully for bent pins and make sure the cooler is not applying uneven pressure; on this platform, socket-contact problems can affect one memory channel and cause dual-stick failures. Updating the motherboard BIOS may also improve memory compatibility, but do it only after restoring stable default settings.
So the goal is to test each stick and slot combination individually, then compare whether one module reports different specifications or produces errors? I wanted to confirm what the tests would help identify before running all of them.