I was able to update my BIOS to version 18, but my system still locks up.
I tried the following with the new BIOS:
 - use factory defaults
 - disable SMT
 - disable SMT with Typical Current Idle
 - all of the above with SVM disabled/enabled
Right now I set the power supply idle control to "Low ..." and will report back.

On a positive note, I got an error message:

Sep 14 13:33:04 user-MS-7B85 kernel: BUG: unable to handle kernel NULL pointer dereference at 0000000000000160
Sep 14 13:33:04 user-MS-7B85 kernel: #PF error: [normal kernel read fault]
Sep 14 13:33:04 user-MS-7B85 kernel: PGD 0 P4D 0 
Sep 14 13:33:04 user-MS-7B85 kernel: Oops: 0000 [#1] SMP NOPTI
Sep 14 13:33:04 user-MS-7B85 kernel: CPU: 6 PID: 1620 Comm: QXcbEventReader Not tainted 5.0.0-27-generic #28~18.04.1-Ubuntu
Sep 14 13:33:04 user-MS-7B85 kernel: Hardware name: Micro-Star International Co., Ltd. MS-7B85/B450 GAMING PRO CARBON AC (MS-7B85), BIOS 1.80 07/22/2019
Sep 14 13:33:04 user-MS-7B85 kernel: RIP: 0010:pick_next_task_fair+0x225/0x6f0
Sep 14 13:33:04 user-MS-7B85 kernel: Code: 40 78 48 3d 80 39 e2 b9 75 6c 4c 8b 65 b0 eb 2a 4c 89 e7 45 31 ed e8 aa c6 ff ff 84 c0 75 41 4c 89 e7 4c 89 ee e8 4b 3b ff ff <4c> 8b a0 60 01 00 00 4d 85 e4 0f 84 e9 00 00 00 4d 8b 6c 24 40 4d
Sep 14 13:33:04 user-MS-7B85 kernel: RSP: 0018:ffffaa51c34ff938 EFLAGS: 00010046
Sep 14 13:33:04 user-MS-7B85 kernel: RAX: 0000000000000000 RBX: ffff8e210e7a2d80 RCX: 000000000000000a
Sep 14 13:33:04 user-MS-7B85 kernel: RDX: ffffaa51c34ff9c0 RSI: 0000000000000000 RDI: ffff8e210e7a2e00
Sep 14 13:33:04 user-MS-7B85 kernel: RBP: ffffaa51c34ff998 R08: 00000000000f48d3 R09: ffff8e2109ca8a00
Sep 14 13:33:04 user-MS-7B85 kernel: R10: ffffaa51c34ff898 R11: 0000000000000001 R12: ffff8e210e7a2e00
Sep 14 13:33:04 user-MS-7B85 kernel: R13: 0000000000000000 R14: ffff8e21089820c0 R15: ffffaa51c34ff9c0
Sep 14 13:33:04 user-MS-7B85 kernel: FS:  00007fa560ab6700(0000) GS:ffff8e210e780000(0000) knlGS:0000000000000000
Sep 14 13:33:04 user-MS-7B85 kernel: CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
Sep 14 13:33:04 user-MS-7B85 kernel: CR2: 0000000000000160 CR3: 00000004081dc000 CR4: 0000000000340ee0
Sep 14 13:33:04 user-MS-7B85 kernel: Call Trace:
Sep 14 13:33:04 user-MS-7B85 kernel:  __schedule+0x173/0x850
Sep 14 13:33:04 user-MS-7B85 kernel:  ? ep_poll_callback+0x93/0x2a0
Sep 14 13:33:04 user-MS-7B85 kernel:  schedule+0x2c/0x70
Sep 14 13:33:04 user-MS-7B85 kernel:  schedule_hrtimeout_range_clock+0x181/0x190
Sep 14 13:33:04 user-MS-7B85 kernel:  ? __wake_up_common+0x73/0x130
Sep 14 13:33:04 user-MS-7B85 kernel:  ? add_wait_queue+0x44/0x50
Sep 14 13:33:04 user-MS-7B85 kernel:  ? __pollwait+0xaf/0xe0
Sep 14 13:33:04 user-MS-7B85 kernel:  schedule_hrtimeout_range+0x13/0x20
Sep 14 13:33:04 user-MS-7B85 kernel:  poll_schedule_timeout.constprop.11+0x46/0x70
Sep 14 13:33:04 user-MS-7B85 kernel:  do_sys_poll+0x3d6/0x590
Sep 14 13:33:04 user-MS-7B85 kernel:  ? kmem_cache_free+0x1a7/0x1d0
Sep 14 13:33:04 user-MS-7B85 kernel:  ? kmem_cache_free+0x1a7/0x1d0
Sep 14 13:33:04 user-MS-7B85 kernel:  ? update_load_avg+0x8b/0x5a0
Sep 14 13:33:04 user-MS-7B85 kernel:  ? update_load_avg+0x8b/0x5a0
Sep 14 13:33:04 user-MS-7B85 kernel:  ? __enqueue_entity+0x5c/0x60
Sep 14 13:33:04 user-MS-7B85 kernel:  ? enqueue_entity+0x111/0x650
Sep 14 13:33:04 user-MS-7B85 kernel:  ? record_times+0x1b/0xc0
Sep 14 13:33:04 user-MS-7B85 kernel:  ? poll_select_copy_remaining+0x1b0/0x1b0
Sep 14 13:33:04 user-MS-7B85 kernel:  ? ttwu_do_wakeup+0x1e/0x140
Sep 14 13:33:04 user-MS-7B85 kernel:  ? ttwu_do_activate+0x77/0x80
Sep 14 13:33:04 user-MS-7B85 kernel:  ? try_to_wake_up+0x59/0x4c0
Sep 14 13:33:04 user-MS-7B85 kernel:  ? default_wake_function+0x12/0x20
Sep 14 13:33:04 user-MS-7B85 kernel:  ? pollwake+0x72/0x90
Sep 14 13:33:04 user-MS-7B85 kernel:  ? wake_up_q+0x80/0x80
Sep 14 13:33:04 user-MS-7B85 kernel:  ? __wake_up_common+0x73/0x130
Sep 14 13:33:04 user-MS-7B85 kernel:  ? __wake_up_locked_key+0x1b/0x20
Sep 14 13:33:04 user-MS-7B85 kernel:  ? vfs_write+0x16a/0x1a0
Sep 14 13:33:04 user-MS-7B85 kernel:  __x64_sys_poll+0x3b/0x140
Sep 14 13:33:04 user-MS-7B85 kernel:  ? __x64_sys_poll+0x3b/0x140
Sep 14 13:33:04 user-MS-7B85 kernel:  do_syscall_64+0x5a/0x120
Sep 14 13:33:04 user-MS-7B85 kernel:  entry_SYSCALL_64_after_hwframe+0x44/0xa9
Sep 14 13:33:04 user-MS-7B85 kernel: RIP: 0033:0x7fa579df3bf9
Sep 14 13:33:04 user-MS-7B85 kernel: Code: 90 41 54 55 41 89 d4 53 48 89 f5 48 89 fb 48 83 ec 10 e8 fa ba 01 00 44 89 e2 41 89 c0 48 89 ee 48 89 df b8 07 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 31 44 89 c7 89 44 24 0c e8 33 bb 01 00 8b 44
Sep 14 13:33:04 user-MS-7B85 kernel: RSP: 002b:00007fa560ab5c20 EFLAGS: 00000293 ORIG_RAX: 0000000000000007
Sep 14 13:33:04 user-MS-7B85 kernel: RAX: ffffffffffffffda RBX: 00007fa560ab5c68 RCX: 00007fa579df3bf9
Sep 14 13:33:04 user-MS-7B85 kernel: RDX: 00000000ffffffff RSI: 0000000000000001 RDI: 00007fa560ab5c68
Sep 14 13:33:04 user-MS-7B85 kernel: RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000005
Sep 14 13:33:04 user-MS-7B85 kernel: R10: 001dd0f901a02da5 R11: 0000000000000293 R12: 00000000ffffffff
Sep 14 13:33:04 user-MS-7B85 kernel: R13: 0000000000000000 R14: 00005626664481c8 R15: 0000000000000000
Sep 14 13:33:04 user-MS-7B85 kernel: Modules linked in: rfcomm cmac bnep edac_mce_amd binfmt_misc kvm irqbypass nls_iso8859_1 crct10dif_pclmul crc32_pclmul ghash_clmulni_intel aesni_intel snd_hda_codec_realtek aes_x86_64 snd_hda_codec_generic crypto_simd cryptd ledtrig_audio glue_helper snd_hda_codec_hdmi btusb btrtl snd_hda_intel btbcm snd_usb_audio btintel snd_hda_codec snd_usbmidi_lib bluetooth snd_hda_core snd_hwdep snd_seq_midi snd_pcm joydev snd_seq_midi_event input_leds wmi_bmof snd_rawmidi ecdh_generic snd_seq snd_seq_device snd_timer snd ccp soundcore mac_hid sch_fq_codel parport_pc ppdev lp parport ip_tables x_tables autofs4 uas usb_storage hid_generic usbhid hid amdgpu chash amd_iommu_v2 gpu_sched ttm drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops drm igb i2c_piix4 dca i2c_algo_bit ahci libahci wmi gpio_amdpt gpio_generic
Sep 14 13:33:04 user-MS-7B85 kernel: CR2: 0000000000000160
Sep 14 13:33:04 user-MS-7B85 kernel: ---[ end trace c1ca7818f368c3a6 ]---
Sep 14 13:33:04 user-MS-7B85 kernel: RIP: 0010:pick_next_task_fair+0x225/0x6f0
Sep 14 13:33:04 user-MS-7B85 kernel: Code: 40 78 48 3d 80 39 e2 b9 75 6c 4c 8b 65 b0 eb 2a 4c 89 e7 45 31 ed e8 aa c6 ff ff 84 c0 75 41 4c 89 e7 4c 89 ee e8 4b 3b ff ff <4c> 8b a0 60 01 00 00 4d 85 e4 0f 84 e9 00 00 00 4d 8b 6c 24 40 4d
Sep 14 13:33:04 user-MS-7B85 kernel: RSP: 0018:ffffaa51c34ff938 EFLAGS: 00010046
Sep 14 13:33:04 user-MS-7B85 kernel: RAX: 0000000000000000 RBX: ffff8e210e7a2d80 RCX: 000000000000000a
Sep 14 13:33:04 user-MS-7B85 kernel: RDX: ffffaa51c34ff9c0 RSI: 0000000000000000 RDI: ffff8e210e7a2e00
Sep 14 13:33:04 user-MS-7B85 kernel: RBP: ffffaa51c34ff998 R08: 00000000000f48d3 R09: ffff8e2109ca8a00
Sep 14 13:33:04 user-MS-7B85 kernel: R10: ffffaa51c34ff898 R11: 0000000000000001 R12: ffff8e210e7a2e00
Sep 14 13:33:04 user-MS-7B85 kernel: R13: 0000000000000000 R14: ffff8e21089820c0 R15: ffffaa51c34ff9c0
Sep 14 13:33:04 user-MS-7B85 kernel: FS:  00007fa560ab6700(0000) GS:ffff8e210e780000(0000) knlGS:0000000000000000
Sep 14 13:33:04 user-MS-7B85 kernel: CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
Sep 14 13:33:04 user-MS-7B85 kernel: CR2: 0000000000000160 CR3: 00000004081dc000 CR4: 0000000000340ee0
Sep 14 13:33:04 user-MS-7B85 kernel: BUG: unable to handle kernel paging request at 00007fa560ab6fff
Sep 14 13:33:04 user-MS-7B85 kernel: #PF error: [INSTR]