Please power off NAS eject HDD & SATA DOM, arrange memtest86+ to verify memory compatibility & system stability, with following steps:
A-1. Make MEMTEST86+ driver
Method1: (newer version)
M1-1 Create from Windows 9x/2K/xp/7, download and execute from your PC and would clean USB driver up and install this tool & bootable:
Method1: Traditional DOS boot
M2-1: We need prepare an USB driver as a Free DOS bootable disk from:
http://rufus.akeo.ie/ or https://github.com/downloads/pbatard/rufus/rufus_v1.1.7f.exe
M2-2: Copy memtest86+-4.20.exe.zip and unzip the MT420.EXE into USB driver.
A-3. Plug USB driver into NAS back panel USB2.0 port, and USB keyboard.
A-4. Power up NAS & N2800/N4800/N5550/N7510/N4510U & press F2 into BIOS. (N2810, N4810, N5810 press DEL)
A-5. Config BIOS boot menu booting from USB driver.
A-6. Boot into DOS, type "MT420.EXE" for memory testing at least 24~48 hours.
B. Since enter the MEMTEST86 and system would auto start testing, as like following link picture, the top line have PASS & TEST running, and at middle left the WALLTIME is running, if get error would could found from middle-right the ERRORS & ECC ERRS.
C. If MEMTEST doesn't running automatically, please help us doign compare test from an normal PC/NB to confirm the USB driver & MEMTEST is correct.
C-1. Take this USB driver into a normal PC/NB, boot from USB and doing MEMTEST 86 tesing, to confirm this USB driver & MEMTEST 86 is wokring.
C-2. Remove the additional memory from NAS and doing the MEMTEST again.