My Early 2008 Mac Pro has worked pretty consistently for a decade but is now spontaneously restarting. It is running OS X 10.10.5 and I see no core updates available. I have avoided updating the OS any further out of fear of system instability; as of recently the hardware became too old for the latest OS X.
I have not installed new software and I thought the spontaneous restarts were due to Firefox (mostly using this computer for online stuff these days) but then it happened when I was in Safari with Firefox not running. I did a disk check which found and repaired an error, but after that the system still restarted -- though now at least I got a panic log.
Does the log (below) indicate where the problem lies? I have been working through a guide to reading panic logs but thus far I can't figure out the problem -- was it trying to read from a memory address that doesn't exist? If so, why would this happen? Thank you very much for considering this.
[StackExchange says my question looks like spam and won't let me post, so I cut out most of the panic log I had pasted below.]
Anonymous UUID: 3D86AB0F-D83A-EC2C-9940-63A3721B44ED Tue Aug 7 19:59:11 2018 *** Panic Report *** panic(cpu 1 caller 0xffffff800d416f72): Kernel trap at 0xffffff800d4179c0, type 6=invalid opcode, registers: CR0: 0x000000008001003b, CR2: 0x000000007be25000, CR3: 0x000000000fe7d000, CR4: 0x0000000000002660 RAX: 0x000000007be25000, RBX: 0x0000000000000012, RCX: 0xffffff8025653c50, RDX: 0xffffff800d4346d0 RSP: 0xffffff817d46e078, RBP: 0xffffff8184d73d70, RSI: 0x0000000000000008, RDI: 0xffffff817d46e080 R8: 0x7ffffffffffffffe, R9: 0x0000010728abd22c, R10: 0x0000000000000000, R11: 0x00000000e0000000 R12: 0xffffff817d46e080, R13: 0xffffff8024f98e40, R14: 0x0000000000000148, R15: 0xffffff817d46e080 RFL: 0x0000000000010082, RIP: 0xffffff800d4179c0, CS: 0x0000000000000008, SS: 0x0000000000000010 Fault CR2: 0x000000007be25000, Error code: 0x0000000000000000, Fault CPU: 0x1 Backtrace (CPU 1), Frame : Return Address 0xffffff817d46dd20 : 0xffffff800d32ae01 0xffffff817d46dda0 : 0xffffff800d416f72 0xffffff817d46df60 : 0xffffff800d433e33 0xffffff817d46df80 : 0xffffff800d4179c0 0xffffff8184d73d70 : 0xffffff7f8ef1b1e9 0xffffff8184d73e60 : 0xffffff7f8ef1a5b4 0xffffff8184d73f20 : 0xffffff800d418b0e 0xffffff8184d73f40 : 0xffffff800d341f6b 0xffffff8184d73f90 : 0xffffff800d3424b0 0xffffff8184d73fb0 : 0xffffff800d411867 Kernel Extensions in backtrace: com.apple.driver.AppleIntelCPUPowerManagement(218.0)[B659F364-9486-3602-A55E-BD7D8E1815B2]@0xffffff7f8ef18000->0xffffff7f8ef42fff BSD process name corresponding to current thread: kernel_task