Example:

https://codereview.chromium.org/1923653002/

win_chromium_rel_ng: 54 mins, 24 secs - https://build.chromium.org/p/tryserver.chromium.win/builders/win_chromium_rel_ng/builds/215738

win_chromium_x64_rel_ng: 1 hrs, 9 mins, 50 secs - https://build.chromium.org/p/tryserver.chromium.win/builders/win_chromium_x64_rel_ng/builds/207898

analyzing this

win_chromium_rel_ng - compile stage -  27 mins, 22 secs 
win_chromium_x64_rel_ng - compile stage - 49 mins, 4 secs

looking at command lines:

compile targets:

win_chromium_rel_ng:

accessibility_unittests accessibility_unittests_run angle_unittests angle_unittests_run app_list_presenter_unittests app_list_presenter_unittests_run app_list_unittests app_list_unittests_run app_shell_unittests app_shell_unittests_run ash_unittests ash_unittests_run aura_unittests aura_unittests_run base_unittests base_unittests_run battor_agent_unittests battor_agent_unittests_run browser_tests browser_tests_run cacheinvalidation_unittests cacheinvalidation_unittests_run cast_unittests cast_unittests_run cc_unittests cc_unittests_run chrome chrome_app_unittests chrome_app_unittests_run chrome_elf_unittests chrome_elf_unittests_run chromedriver_unittests chromedriver_unittests_run chromium_builder_tests components_browsertests components_browsertests_run components_unittests components_unittests_run compositor_unittests compositor_unittests_run content_browsertests content_browsertests_run content_unittests content_unittests_run courgette_unittests courgette_unittests_run crypto_unittests crypto_unittests_run device_unittests device_unittests_run display_unittests display_unittests_run events_unittests events_unittests_run extensions_browsertests extensions_browsertests_run extensions_unittests extensions_unittests_run gcm_unit_tests gcm_unit_tests_run gfx_unittests gfx_unittests_run gin_unittests gin_unittests_run gl_tests gl_tests_run gl_unittests gl_unittests_run gn_unittests gn_unittests_run google_apis_unittests google_apis_unittests_run gpu_unittests gpu_unittests_run installer_util_unittests installer_util_unittests_run interactive_ui_tests interactive_ui_tests_run ipc_tests ipc_tests_run jingle_unittests jingle_unittests_run keyboard_unittests media_blink_unittests media_blink_unittests_run media_unittests media_unittests_run message_center_unittests message_center_unittests_run midi_unittests midi_unittests_run mini_installer mojo_common_unittests mojo_common_unittests_run mojo_public_bindings_unittests mojo_public_bindings_unittests_run mojo_public_system_unittests mojo_public_system_unittests_run mojo_system_unittests mojo_system_unittests_run nacl_loader_unittests nacl_loader_unittests_run net_unittests net_unittests_run ppapi_unittests ppapi_unittests_run printing_unittests printing_unittests_run remoting_unittests remoting_unittests_run sbox_integration_tests sbox_integration_tests_run sbox_unittests sbox_unittests_run sbox_validation_tests sbox_validation_tests_run setup_unittests setup_unittests_run skia_unittests skia_unittests_run sql_unittests sql_unittests_run sync_integration_tests sync_integration_tests_run sync_unit_tests sync_unit_tests_run tab_capture_end2end_tests_run telemetry_gpu_test_run telemetry_gpu_unittests_run telemetry_perf_unittests_run telemetry_unittests_run ui_base_unittests ui_base_unittests_run ui_touch_selection_unittests ui_touch_selection_unittests_run unit_tests unit_tests_run url_unittests url_unittests_run views_unittests views_unittests_run wm_unittests wm_unittests_run

win_chromium_x64_rel_ng:

accessibility_unittests accessibility_unittests_run app_list_presenter_unittests app_list_presenter_unittests_run app_list_unittests app_list_unittests_run app_shell_unittests app_shell_unittests_run ash_unittests ash_unittests_run aura_unittests aura_unittests_run base_unittests base_unittests_run battor_agent_unittests battor_agent_unittests_run browser_tests browser_tests_run cacheinvalidation_unittests cacheinvalidation_unittests_run cast_unittests cast_unittests_run cc_unittests cc_unittests_run chrome chrome_app_unittests chrome_app_unittests_run chrome_elf_unittests chrome_elf_unittests_run chromedriver_unittests chromedriver_unittests_run components_browsertests components_browsertests_run components_unittests components_unittests_run compositor_unittests compositor_unittests_run content_browsertests content_browsertests_run content_unittests content_unittests_run courgette_unittests courgette_unittests_run crypto_unittests crypto_unittests_run device_unittests device_unittests_run display_unittests display_unittests_run events_unittests events_unittests_run extensions_browsertests extensions_browsertests_run extensions_unittests extensions_unittests_run gcm_unit_tests gcm_unit_tests_run gfx_unittests gfx_unittests_run gn_all gn_unittests gn_unittests_run google_apis_unittests google_apis_unittests_run gpu_unittests gpu_unittests_run installer_util_unittests installer_util_unittests_run interactive_ui_tests interactive_ui_tests_run ipc_tests ipc_tests_run jingle_unittests jingle_unittests_run keyboard_unittests media_blink_unittests media_blink_unittests_run media_unittests media_unittests_run message_center_unittests message_center_unittests_run midi_unittests midi_unittests_run mini_installer mojo_common_unittests mojo_common_unittests_run mojo_public_bindings_unittests mojo_public_bindings_unittests_run mojo_public_system_unittests mojo_public_system_unittests_run mojo_system_unittests mojo_system_unittests_run nacl_loader_unittests nacl_loader_unittests_run net_unittests net_unittests_run ppapi_unittests ppapi_unittests_run printing_unittests printing_unittests_run remoting_unittests remoting_unittests_run sbox_integration_tests sbox_integration_tests_run sbox_unittests sbox_unittests_run sbox_validation_tests sbox_validation_tests_run setup_unittests setup_unittests_run skia_unittests skia_unittests_run sql_unittests sql_unittests_run sync_integration_tests sync_integration_tests_run sync_unit_tests sync_unit_tests_run telemetry_gpu_unittests_run telemetry_perf_unittests_run telemetry_unittests_run ui_base_unittests ui_base_unittests_run ui_touch_selection_unittests ui_touch_selection_unittests_run unit_tests unit_tests_run url_unittests url_unittests_run views_unittests views_unittests_run wm_unittests wm_unittests_run

comparing these, the differences are:

ONLY IN win_chromium_rel_ng:

angle_unittests
angle_unittests_run
chromium_builder_tests
gin_unittests
gin_unittests_run
gl_tests
gl_tests_run
gl_unittests
gl_unittests_run
tab_capture_end2end_tests_run
telemetry_gpu_test_run

ONLY IN win_chromium_x64_rel_ng:

gn_all

conclusion is that gn_all is perhaps slowing down win_chromium_x64_rel_ng?

Understood that x64 has switched to GN, but why is chromium_builder_tests in win_chromium_rel_ng and why is gn_all in win_chromium_x64_rel_ng, when the targets should be being picked by analyze?