Testing forman 1.8 rc3 and have enabled Organization and Location support for the first time. With 500 - 2,000 nodes assigned the response time is slow but workable, even 2500 nodes take quite a bit longer. On Locations or Organizations with 7000 + nodes assigned it seems to spin forever.

2015-04-14 16:52:14 [D] Host::Managed Load (168.9ms) SELECT "hosts".* FROM "hosts" WHERE "hosts"."organization_id" = 7 AND "hosts"."type" IN ('Host::Managed') AND (hosts.operatingsystem_id IS NOT NULL)
2015-04-14 16:52:16 [D] ConfigTemplate Load (1.2ms) SELECT "config_templates".* FROM "config_templates" INNER JOIN "config_templates_operatingsystems" ON "config_templates_operatingsystems"."config_template_id" = "config_templates"."id" INNER JOIN "operatingsystems" ON "operatingsystems"."id" = "config_templates_operatingsystems"."operatingsystem_id" INNER JOIN "template_kinds" ON "template_kinds"."id" = "config_templates"."template_kind_id" INNER JOIN "template_combinations" ON "template_combinations"."config_template_id" = "config_templates"."id" WHERE "operatingsystems"."id" = 8 AND "template_kinds"."name" = 'provision' AND "template_combinations"."hostgroup_id" IS NULL AND "template_combinations"."environment_id" = 1 ORDER BY config_templates.name LIMIT 1
2015-04-14 16:52:16 [D] ConfigTemplate Load (0.8ms) SELECT "config_templates".* FROM "config_templates" INNER JOIN "config_templates_operatingsystems" ON "config_templates_operatingsystems"."config_template_id" = "config_templates"."id" INNER JOIN "operatingsystems" ON "operatingsystems"."id" = "config_templates_operatingsystems"."operatingsystem_id" INNER JOIN "template_kinds" ON "template_kinds"."id" = "config_templates"."template_kind_id" INNER JOIN "os_default_templates" ON "os_default_templates"."config_template_id" = "config_templates"."id" WHERE "operatingsystems"."id" = 8 AND "template_kinds"."name" = 'provision' AND "os_default_templates"."operatingsystem_id" = 8 ORDER BY config_templates.name LIMIT 1