diff --git a/conduwuit-example.toml b/conduwuit-example.toml
index 541050b1..5b66044a 100644
--- a/conduwuit-example.toml
+++ b/conduwuit-example.toml
@@ -1066,7 +1066,7 @@
 # 3 to 5 = Statistics with possible performance impact.
 # 6 = All statistics.
 #
-#rocksdb_stats_level = 1
+#rocksdb_stats_level = 3
 
 # This is a password that can be configured that will let you login to the
 # server bot account (currently `@conduit`) for emergency troubleshooting
@@ -1680,11 +1680,9 @@
 #stream_amplification = 1024
 
 # Number of sender task workers; determines sender parallelism. Default is
-# '0' which means the value is determined internally, likely matching the
-# number of tokio worker-threads or number of cores, etc. Override by
-# setting a non-zero value.
+# number of CPU cores. Override by setting a different value.
 #
-#sender_workers = 0
+#sender_workers = 4
 
 # Enables listener sockets; can be set to false to disable listening. This
 # option is intended for developer/diagnostic purposes only.
diff --git a/src/core/config/mod.rs b/src/core/config/mod.rs
index aa021be7..6cbda97e 100644
--- a/src/core/config/mod.rs
+++ b/src/core/config/mod.rs
@@ -1235,7 +1235,7 @@ pub struct Config {
 	/// 3 to 5 = Statistics with possible performance impact.
 	/// 6 = All statistics.
 	///
-	/// default: 1
+	/// default: 3
 	#[serde(default = "default_rocksdb_stats_level")]
 	pub rocksdb_stats_level: u8,
 
@@ -1917,12 +1917,10 @@ pub struct Config {
 	pub stream_amplification: usize,
 
 	/// Number of sender task workers; determines sender parallelism. Default is
-	/// '0' which means the value is determined internally, likely matching the
-	/// number of tokio worker-threads or number of cores, etc. Override by
-	/// setting a non-zero value.
+	/// core count. Override by setting a different value.
 	///
-	/// default: 0
-	#[serde(default)]
+	/// default: core count
+	#[serde(default = "default_sender_workers")]
 	pub sender_workers: usize,
 
 	/// Enables listener sockets; can be set to false to disable listening. This
@@ -2153,45 +2151,48 @@ fn default_database_backups_to_keep() -> i16 { 1 }
 
 fn default_db_write_buffer_capacity_mb() -> f64 { 48.0 + parallelism_scaled_f64(4.0) }
 
-fn default_db_cache_capacity_mb() -> f64 { 128.0 + parallelism_scaled_f64(64.0) }
+fn default_db_cache_capacity_mb() -> f64 { 512.0 + parallelism_scaled_f64(512.0) }
 
-fn default_pdu_cache_capacity() -> u32 { parallelism_scaled_u32(10_000).saturating_add(100_000) }
+fn default_pdu_cache_capacity() -> u32 { parallelism_scaled_u32(50_000).saturating_add(100_000) }
 
 fn default_cache_capacity_modifier() -> f64 { 1.0 }
 
 fn default_auth_chain_cache_capacity() -> u32 {
-	parallelism_scaled_u32(10_000).saturating_add(100_000)
-}
-
-fn default_shorteventid_cache_capacity() -> u32 {
 	parallelism_scaled_u32(50_000).saturating_add(100_000)
 }
 
+fn default_shorteventid_cache_capacity() -> u32 {
+	parallelism_scaled_u32(100_000).saturating_add(100_000)
+}
+
 fn default_eventidshort_cache_capacity() -> u32 {
-	parallelism_scaled_u32(25_000).saturating_add(100_000)
+	parallelism_scaled_u32(50_000).saturating_add(100_000)
 }
 
 fn default_eventid_pdu_cache_capacity() -> u32 {
-	parallelism_scaled_u32(25_000).saturating_add(100_000)
+	parallelism_scaled_u32(50_000).saturating_add(100_000)
 }
 
 fn default_shortstatekey_cache_capacity() -> u32 {
-	parallelism_scaled_u32(10_000).saturating_add(100_000)
+	parallelism_scaled_u32(50_000).saturating_add(100_000)
 }
 
 fn default_statekeyshort_cache_capacity() -> u32 {
-	parallelism_scaled_u32(10_000).saturating_add(100_000)
+	parallelism_scaled_u32(50_000).saturating_add(100_000)
 }
 
 fn default_servernameevent_data_cache_capacity() -> u32 {
-	parallelism_scaled_u32(100_000).saturating_add(500_000)
+	parallelism_scaled_u32(100_000).saturating_add(100_000)
 }
 
-fn default_stateinfo_cache_capacity() -> u32 { parallelism_scaled_u32(100) }
+fn default_stateinfo_cache_capacity() -> u32 {
+	parallelism_scaled_u32(500).clamp(100, 12000)
+}
 
-fn default_roomid_spacehierarchy_cache_capacity() -> u32 { parallelism_scaled_u32(1000) }
+fn default_roomid_spacehierarchy_cache_capacity() -> u32 {
+	parallelism_scaled_u32(500).clamp(100, 12000) }
 
-fn default_dns_cache_entries() -> u32 { 32768 }
+fn default_dns_cache_entries() -> u32 { 327680 }
 
 fn default_dns_min_ttl() -> u64 { 60 * 180 }
 
@@ -2297,7 +2298,7 @@ fn default_typing_client_timeout_max_s() -> u64 { 45 }
 
 fn default_rocksdb_recovery_mode() -> u8 { 1 }
 
-fn default_rocksdb_log_level() -> String { "error".to_owned() }
+fn default_rocksdb_log_level() -> String { "info".to_owned() }
 
 fn default_rocksdb_log_time_to_roll() -> usize { 0 }
 
@@ -2329,7 +2330,7 @@ fn default_rocksdb_compression_level() -> i32 { 32767 }
 #[allow(clippy::doc_markdown)]
 fn default_rocksdb_bottommost_compression_level() -> i32 { 32767 }
 
-fn default_rocksdb_stats_level() -> u8 { 1 }
+fn default_rocksdb_stats_level() -> u8 { 3 }
 
 // I know, it's a great name
 #[must_use]
@@ -2384,14 +2385,13 @@ fn default_admin_log_capture() -> String {
 fn default_admin_room_tag() -> String { "m.server_notice".to_owned() }
 
 #[allow(clippy::as_conversions, clippy::cast_precision_loss)]
-fn parallelism_scaled_f64(val: f64) -> f64 { val * (sys::available_parallelism() as f64) }
+pub fn parallelism_scaled_f64(val: f64) -> f64 { val * (sys::available_parallelism() as f64) }
 
-fn parallelism_scaled_u32(val: u32) -> u32 {
-	let val = val.try_into().expect("failed to cast u32 to usize");
-	parallelism_scaled(val).try_into().unwrap_or(u32::MAX)
-}
+pub fn parallelism_scaled_u32(val: u32) -> u32 { val.saturating_mul(sys::available_parallelism() as u32) }
 
-fn parallelism_scaled(val: usize) -> usize { val.saturating_mul(sys::available_parallelism()) }
+pub fn parallelism_scaled_i32(val: i32) -> i32 { val.saturating_mul(sys::available_parallelism() as i32) }
+
+pub fn parallelism_scaled(val: usize) -> usize { val.saturating_mul(sys::available_parallelism()) }
 
 fn default_trusted_server_batch_size() -> usize { 256 }
 
@@ -2411,6 +2411,8 @@ fn default_stream_width_scale() -> f32 { 1.0 }
 
 fn default_stream_amplification() -> usize { 1024 }
 
+fn default_sender_workers() -> usize { parallelism_scaled(1) }
+
 fn default_client_receive_timeout() -> u64 { 75 }
 
 fn default_client_request_timeout() -> u64 { 180 }
diff --git a/src/core/matrix/state_res/event_auth.rs b/src/core/matrix/state_res/event_auth.rs
index 77a4a95c..ec70d684 100644
--- a/src/core/matrix/state_res/event_auth.rs
+++ b/src/core/matrix/state_res/event_auth.rs
@@ -13,6 +13,7 @@ use ruma::{
 		power_levels::RoomPowerLevelsEventContent,
 		third_party_invite::RoomThirdPartyInviteEventContent,
 	},
+	EventId,
 	int,
 	serde::{Base64, Raw},
 };
@@ -21,7 +22,6 @@ use serde::{
 	de::{Error as _, IgnoredAny},
 };
 use serde_json::{from_str as from_json_str, value::RawValue as RawJsonValue};
-
 use super::{
 	Error, Event, Result, StateEventType, StateKey, TimelineEventType,
 	power_levels::{
@@ -149,8 +149,8 @@ where
 	for<'a> &'a E: Event + Send,
 {
 	debug!(
-		event_id = %incoming_event.event_id(),
-		event_type = ?incoming_event.event_type(),
+		event_id = format!("{}", incoming_event.event_id()),
+		event_type = format!("{}", incoming_event.event_type()),
 		"auth_check beginning"
 	);
 
@@ -219,7 +219,7 @@ where
 	/*
 	// TODO: In the past this code was commented as it caused problems with Synapse. This is no
 	// longer the case. This needs to be implemented.
-	// See also: https://github.com/ruma/ruma/pull/2064
+	// See also: https://github.com/ruma/ruma/pull/2064    
 	//
 	// 2. Reject if auth_events
 	// a. auth_events cannot have duplicate keys since it's a BTree
@@ -242,20 +242,44 @@ where
 	}
 	*/
 
-	let (room_create_event, power_levels_event, sender_member_event) = join3(
-		fetch_state(&StateEventType::RoomCreate, ""),
-		fetch_state(&StateEventType::RoomPowerLevels, ""),
-		fetch_state(&StateEventType::RoomMember, sender.as_str()),
-	)
-	.await;
+	// let (room_create_event, power_levels_event, sender_member_event) = join3(
+	// 	fetch_state(&StateEventType::RoomCreate, ""),
+	// 	fetch_state(&StateEventType::RoomPowerLevels, ""),
+	// 	fetch_state(&StateEventType::RoomMember, sender.as_str()),
+	// )
+	// .await;
+
+	let room_create_event = fetch_state(&StateEventType::RoomCreate, "").await;
+	let power_levels_event = fetch_state(&StateEventType::RoomPowerLevels, "").await;
+	let sender_member_event = fetch_state(&StateEventType::RoomMember, sender.as_str()).await;
 
 	let room_create_event = match room_create_event {
 		| None => {
-			warn!("no m.room.create event in auth chain");
+			error!(
+				create_event = room_create_event.as_ref().map(Event::event_id).unwrap_or(<&EventId>::try_from("$unknown").unwrap()).as_str(),
+				power_levels = power_levels_event.as_ref().map(Event::event_id).unwrap_or(<&EventId>::try_from("$unknown").unwrap()).as_str(),
+				member_event = sender_member_event.as_ref().map(Event::event_id).unwrap_or(<&EventId>::try_from("$unknown").unwrap()).as_str(),
+				"no m.room.create event found for {} ({})!",
+				incoming_event.event_id().as_str(),
+				incoming_event.room_id().as_str()
+			);
 			return Ok(false);
 		},
 		| Some(e) => e,
 	};
+	// just re-check 1.2 to work around a bug
+	let Some(room_id_server_name) = incoming_event.room_id().server_name() else {
+		warn!("room ID has no servername");
+		return Ok(false);
+	};
+
+	if room_id_server_name != room_create_event.sender().server_name() {
+		warn!(
+			"servername of room ID origin ({}) does not match servername of m.room.create sender ({})",
+			room_id_server_name,
+			room_create_event.sender().server_name());
+		return Ok(false);
+	}
 
 	if incoming_event.room_id() != room_create_event.room_id() {
 		warn!("room_id of incoming event does not match room_id of m.room.create event");
diff --git a/src/core/matrix/state_res/mod.rs b/src/core/matrix/state_res/mod.rs
index ce9d9276..ba9c013d 100644
--- a/src/core/matrix/state_res/mod.rs
+++ b/src/core/matrix/state_res/mod.rs
@@ -733,8 +733,12 @@ where
 	Fut: Future<Output = Option<E>> + Send,
 	E: Event + Send + Sync,
 {
+	let mut room_id = None;
 	while let Some(sort_ev) = event {
 		debug!(event_id = sort_ev.event_id().as_str(), "mainline");
+		if room_id.is_none() {
+			room_id = Some(sort_ev.room_id().to_owned());
+		}
 
 		let id = sort_ev.event_id();
 		if let Some(depth) = mainline_map.get(id) {
@@ -753,7 +757,7 @@ where
 			}
 		}
 	}
-	// Did not find a power level event so we default to zero
+	warn!("could not find a power event in the mainline map for {room_id:?}, defaulting to zero depth");
 	Ok(0)
 }
 
diff --git a/src/database/engine/cf_opts.rs b/src/database/engine/cf_opts.rs
index 58358f02..b8d0b307 100644
--- a/src/database/engine/cf_opts.rs
+++ b/src/database/engine/cf_opts.rs
@@ -29,7 +29,7 @@ fn descriptor_cf_options(
 	set_table_options(&mut opts, &desc, cache)?;
 
 	opts.set_min_write_buffer_number(1);
-	opts.set_max_write_buffer_number(2);
+	opts.set_max_write_buffer_number(3);
 	opts.set_write_buffer_size(desc.write_size);
 
 	opts.set_target_file_size_base(desc.file_size);
diff --git a/src/database/engine/db_opts.rs b/src/database/engine/db_opts.rs
index 18cec742..1299443d 100644
--- a/src/database/engine/db_opts.rs
+++ b/src/database/engine/db_opts.rs
@@ -1,8 +1,6 @@
-use std::{cmp, convert::TryFrom};
-
-use conduwuit::{Config, Result, utils};
+use conduwuit::{Config, Result};
 use rocksdb::{Cache, DBRecoveryMode, Env, LogLevel, Options, statistics::StatsLevel};
-
+use conduwuit::config::{parallelism_scaled_i32, parallelism_scaled_u32};
 use super::{cf_opts::cache_size_f64, logger::handle as handle_log};
 
 /// Create database-wide options suitable for opening the database. This also
@@ -23,8 +21,8 @@ pub(crate) fn db_options(config: &Config, env: &Env, row_cache: &Cache) -> Resul
 	set_logging_defaults(&mut opts, config);
 
 	// Processing
-	opts.set_max_background_jobs(num_threads::<i32>(config)?);
-	opts.set_max_subcompactions(num_threads::<u32>(config)?);
+	opts.set_max_background_jobs(parallelism_scaled_i32(1));
+	opts.set_max_subcompactions(parallelism_scaled_u32(1));
 	opts.set_avoid_unnecessary_blocking_io(true);
 	opts.set_max_file_opening_threads(0);
 
@@ -126,15 +124,3 @@ fn set_logging_defaults(opts: &mut Options, config: &Config) {
 		opts.set_callback_logger(rocksdb_log_level, &handle_log);
 	}
 }
-
-fn num_threads<T: TryFrom<usize>>(config: &Config) -> Result<T> {
-	const MIN_PARALLELISM: usize = 2;
-
-	let requested = if config.rocksdb_parallelism_threads != 0 {
-		config.rocksdb_parallelism_threads
-	} else {
-		utils::available_parallelism()
-	};
-
-	utils::math::try_into::<T, usize>(cmp::max(MIN_PARALLELISM, requested))
-}
diff --git a/src/service/presence/mod.rs b/src/service/presence/mod.rs
index 8f646be6..876d8bee 100644
--- a/src/service/presence/mod.rs
+++ b/src/service/presence/mod.rs
@@ -100,7 +100,7 @@ impl Service {
 	/// Pings the presence of the given user in the given room, setting the
 	/// specified state.
 	pub async fn ping_presence(&self, user_id: &UserId, new_state: &PresenceState) -> Result<()> {
-		const REFRESH_TIMEOUT: u64 = 60 * 1000;
+		const REFRESH_TIMEOUT: u64 = 60 * 1000 * 4;
 
 		let last_presence = self.db.get_presence(user_id).await;
 		let state_changed = match last_presence {
diff --git a/src/service/resolver/actual.rs b/src/service/resolver/actual.rs
index d23ef95a..52cd5d7d 100644
--- a/src/service/resolver/actual.rs
+++ b/src/service/resolver/actual.rs
@@ -306,28 +306,25 @@ impl super::Service {
 
 	#[tracing::instrument(name = "srv", level = "debug", skip(self))]
 	async fn query_srv_record(&self, hostname: &'_ str) -> Result<Option<FedDest>> {
-		let hostnames =
-			[format!("_matrix-fed._tcp.{hostname}."), format!("_matrix._tcp.{hostname}.")];
+		self.services.server.check_running()?;
 
-		for hostname in hostnames {
-			self.services.server.check_running()?;
+		debug!("querying SRV for {hostname:?}");
 
-			debug!("querying SRV for {hostname:?}");
-			let hostname = hostname.trim_end_matches('.');
-			match self.resolver.resolver.srv_lookup(hostname).await {
-				| Err(e) => Self::handle_resolve_error(&e, hostname)?,
-				| Ok(result) => {
-					return Ok(result.iter().next().map(|result| {
-						FedDest::Named(
-							result.target().to_string().trim_end_matches('.').to_owned(),
-							format!(":{}", result.port())
-								.as_str()
-								.try_into()
-								.unwrap_or_else(|_| FedDest::default_port()),
-						)
-					}));
-				},
-			}
+		let hostname_suffix = format!("_matrix-fed._tcp.{hostname}.");
+		let hostname = hostname_suffix.trim_end_matches('.');
+		match self.resolver.resolver.srv_lookup(hostname).await {
+			| Err(e) => Self::handle_resolve_error(&e, hostname)?,
+			| Ok(result) => {
+				return Ok(result.iter().next().map(|result| {
+					FedDest::Named(
+						result.target().to_string().trim_end_matches('.').to_owned(),
+						format!(":{}", result.port())
+							.as_str()
+							.try_into()
+							.unwrap_or_else(|_| FedDest::default_port()),
+					)
+				}));
+			},
 		}
 
 		Ok(None)
diff --git a/src/service/resolver/dns.rs b/src/service/resolver/dns.rs
index 3a0b2551..6856853e 100644
--- a/src/service/resolver/dns.rs
+++ b/src/service/resolver/dns.rs
@@ -53,9 +53,9 @@ impl Resolver {
 		opts.cache_size = config.dns_cache_entries as usize;
 		opts.preserve_intermediates = true;
 		opts.negative_min_ttl = Some(Duration::from_secs(config.dns_min_ttl_nxdomain));
-		opts.negative_max_ttl = Some(Duration::from_secs(60 * 60 * 24 * 30));
+		opts.negative_max_ttl = Some(Duration::from_secs(60 * 60 * 24));
 		opts.positive_min_ttl = Some(Duration::from_secs(config.dns_min_ttl));
-		opts.positive_max_ttl = Some(Duration::from_secs(60 * 60 * 24 * 7));
+		opts.positive_max_ttl = Some(Duration::from_secs(60 * 60 * 24));
 		opts.timeout = Duration::from_secs(config.dns_timeout);
 		opts.attempts = config.dns_attempts as usize;
 		opts.try_tcp_on_error = config.dns_tcp_fallback;
diff --git a/src/service/rooms/event_handler/fetch_and_handle_outliers.rs b/src/service/rooms/event_handler/fetch_and_handle_outliers.rs
index 59b768f2..c72cce87 100644
--- a/src/service/rooms/event_handler/fetch_and_handle_outliers.rs
+++ b/src/service/rooms/event_handler/fetch_and_handle_outliers.rs
@@ -79,7 +79,7 @@ where
 			{
 				// Exponential backoff
 				const MIN_DURATION: u64 = 60 * 2;
-				const MAX_DURATION: u64 = 60 * 60 * 8;
+				const MAX_DURATION: u64 = 60 * 60;
 				if continue_exponential_backoff_secs(
 					MIN_DURATION,
 					MAX_DURATION,
diff --git a/src/service/rooms/event_handler/handle_outlier_pdu.rs b/src/service/rooms/event_handler/handle_outlier_pdu.rs
index d79eed77..fad9ac74 100644
--- a/src/service/rooms/event_handler/handle_outlier_pdu.rs
+++ b/src/service/rooms/event_handler/handle_outlier_pdu.rs
@@ -122,10 +122,7 @@ where
 	}
 
 	// The original create event must be in the auth events
-	if !matches!(
-		auth_events.get(&(StateEventType::RoomCreate, String::new().into())),
-		Some(_) | None
-	) {
+	if !auth_events.contains_key(&(StateEventType::RoomCreate, String::new().into())) {
 		return Err!(Request(InvalidParam("Incoming event refers to wrong create event.")));
 	}
 
diff --git a/src/service/rooms/event_handler/handle_prev_pdu.rs b/src/service/rooms/event_handler/handle_prev_pdu.rs
index cb4978d9..c786599a 100644
--- a/src/service/rooms/event_handler/handle_prev_pdu.rs
+++ b/src/service/rooms/event_handler/handle_prev_pdu.rs
@@ -46,7 +46,7 @@ where
 	{
 		// Exponential backoff
 		const MIN_DURATION: u64 = 5 * 60;
-		const MAX_DURATION: u64 = 60 * 60 * 24;
+		const MAX_DURATION: u64 = 60 * 60;
 		if continue_exponential_backoff_secs(MIN_DURATION, MAX_DURATION, time.elapsed(), *tries) {
 			debug!(
 				?tries,
diff --git a/src/service/rooms/event_handler/upgrade_outlier_pdu.rs b/src/service/rooms/event_handler/upgrade_outlier_pdu.rs
index d2e0623c..1b6b8af5 100644
--- a/src/service/rooms/event_handler/upgrade_outlier_pdu.rs
+++ b/src/service/rooms/event_handler/upgrade_outlier_pdu.rs
@@ -5,7 +5,7 @@ use conduwuit::{
 	matrix::{Event, EventTypeExt, PduEvent, StateKey, state_res},
 	trace,
 	utils::stream::{BroadbandExt, ReadyExt},
-	warn,
+	warn
 };
 use futures::{FutureExt, StreamExt, future::ready};
 use ruma::{CanonicalJsonValue, RoomId, ServerName, events::StateEventType};
@@ -175,7 +175,7 @@ where
 	let extremities: Vec<_> = self
 		.services
 		.state
-		.get_forward_extremities(room_id)
+		.get_forward_extremities(room_id, &state_lock)
 		.map(ToOwned::to_owned)
 		.ready_filter(|event_id| {
 			// Remove any that are referenced by this incoming event's prev_events
@@ -193,6 +193,8 @@ where
 		.collect()
 		.await;
 
+	if extremities.len() == 0 { info!("Retained zero extremities when upgrading outlier PDU to timeline PDU with {} previous events, event id: {}", incoming_pdu.prev_events.len(), incoming_pdu.event_id) }
+	
 	debug!(
 		"Retained {} extremities checked against {} prev_events",
 		extremities.len(),
diff --git a/src/service/rooms/state/mod.rs b/src/service/rooms/state/mod.rs
index 641aa6a9..92881126 100644
--- a/src/service/rooms/state/mod.rs
+++ b/src/service/rooms/state/mod.rs
@@ -388,6 +388,7 @@ impl Service {
 	pub fn get_forward_extremities<'a>(
 		&'a self,
 		room_id: &'a RoomId,
+		_state_lock: &'a RoomMutexGuard,
 	) -> impl Stream<Item = &EventId> + Send + '_ {
 		let prefix = (room_id, Interfix);
 
diff --git a/src/service/rooms/timeline/create.rs b/src/service/rooms/timeline/create.rs
index 6732cd8e..188e71a4 100644
--- a/src/service/rooms/timeline/create.rs
+++ b/src/service/rooms/timeline/create.rs
@@ -42,7 +42,7 @@ pub async fn create_hash_and_sign_event(
 	let prev_events: Vec<OwnedEventId> = self
 		.services
 		.state
-		.get_forward_extremities(room_id)
+		.get_forward_extremities(room_id, _mutex_lock)
 		.take(20)
 		.map(Into::into)
 		.collect()
diff --git a/src/service/sending/mod.rs b/src/service/sending/mod.rs
index 08ca7010..ce687551 100644
--- a/src/service/sending/mod.rs
+++ b/src/service/sending/mod.rs
@@ -401,16 +401,10 @@ impl Service {
 
 fn num_senders(args: &crate::Args<'_>) -> usize {
 	const MIN_SENDERS: usize = 1;
-	// Limit the number of senders to the number of workers threads or number of
-	// cores, conservatively.
-	let max_senders = args
-		.server
-		.metrics
-		.num_workers()
-		.min(available_parallelism());
+	// Limit the maximum number of senders to the number of cores.
+	let max_senders = available_parallelism();
 
-	// If the user doesn't override the default 0, this is intended to then default
-	// to 1 for now as multiple senders is experimental.
+	// default is 4 senders. clamp between 1 and core count.
 	args.server
 		.config
 		.sender_workers