Note 2 Keeps Rebooting

My Note 2 is rooted/bootloader unlocked with CASUAL. Running Beans stock 4.3 ROM. The phone worked GREAT for over a year but a few months ago, apps began to close randomly and the phone would reboot frequently.

So I decided to wipe the phone and start over. I have done this twice and the issue persists. The last time I wiped the phone, I flashed the stock recovery and wiped it multiple times (wipe cache & factory reset).

Then I reflashed the firmware, the ROM and the radio.

However, the phone is still rebooting several times a day.

I have tried 4 different batteries and it doesn't make a difference.

Any ideas? Is there a way to determine if there is something physically wrong with the phone, i.e. bad memory or processor?

Thanks