diff --git a/tests/ChatClient.hs b/tests/ChatClient.hs
index 0dde5f02f9..0a5c8425fe 100644
--- a/tests/ChatClient.hs
+++ b/tests/ChatClient.hs
@@ -436,8 +436,11 @@ testChatN cfg opts ps test params =
 (<//) cc t = timeout t (getTermLine cc) `shouldReturn` Nothing
 
 getTermLine :: HasCallStack => TestCC -> IO String
-getTermLine cc@TestCC {printOutput} =
-  5000000 `timeout` atomically (readTQueue $ termQ cc) >>= \case
+getTermLine cc = getTermLine' 5000000 cc
+
+getTermLine' :: HasCallStack => Int -> TestCC -> IO String
+getTermLine' timeout' cc@TestCC {printOutput} =
+  timeout' `timeout` atomically (readTQueue $ termQ cc) >>= \case
     Just s -> do
       -- remove condition to always echo virtual terminal
       -- when True $ do
@@ -445,7 +448,7 @@ getTermLine cc@TestCC {printOutput} =
         name <- userName cc
         putStrLn $ name <> ": " <> s
       pure s
-    _ -> error "no output for 5 seconds"
+    _ -> error $ "no output for " <> show timeout' <> " microseconds"
 
 userName :: TestCC -> IO [Char]
 userName (TestCC ChatController {currentUser} _ _ _ _ _) =
diff --git a/tests/ChatTests/Groups.hs b/tests/ChatTests/Groups.hs
index b997a95053..ad13cac8bd 100644
--- a/tests/ChatTests/Groups.hs
+++ b/tests/ChatTests/Groups.hs
@@ -15,14 +15,15 @@ import ChatClient
 import ChatTests.DBUtils
 import ChatTests.Utils
 import Control.Concurrent (threadDelay)
-import Control.Concurrent.Async (concurrently_)
-import Control.Monad (forM_, void, when)
+import Control.Concurrent.Async (concurrently_, forConcurrently_)
+import Control.Monad (forM, forM_, void, when)
 import Data.Bifunctor (second)
 import qualified Data.ByteString.Char8 as B
 import Data.Int (Int64)
 import Data.List (intercalate, isInfixOf)
 import qualified Data.Map.Strict as M
 import qualified Data.Text as T
+import Data.Time.Clock (diffUTCTime, getCurrentTime)
 import Simplex.Chat.Controller (ChatConfig (..), ChatHooks (..), defaultChatHooks)
 import Simplex.Chat.Library.Internal (uniqueMsgMentions, updatedMentionNames)
 import Simplex.Chat.Markdown (parseMaybeMarkdownList)
@@ -36,6 +37,7 @@ import Simplex.Messaging.Agent.RetryInterval
 import qualified Simplex.Messaging.Agent.Store.DB as DB
 import Simplex.Messaging.Server.Env.STM hiding (subscriptions)
 import Simplex.Messaging.Transport
+import Simplex.Messaging.Util
 import Simplex.Messaging.Version
 import Test.Hspec hiding (it)
 #if defined(dbPostgres)
@@ -236,7 +238,7 @@ chatGroupTests = do
         it "number of recipients is equal to bucket size (3/3)" (testChannelsRelayDeliverLoop 3)
       it "sender should deduplicate their own messages" testChannelsSenderDeduplicateOwn
       describe "stress test" $ do
-        it "deliver to 10,000 members" (testChannelsRelayDeliverStress 10_000)
+        fit "deliver to 1000 members" (testChannelsRelayDeliverStress 1000)
 
 testGroupCheckMessages :: HasCallStack => TestParams -> IO ()
 testGroupCheckMessages =
@@ -8337,29 +8339,35 @@ testChannelsSenderDeduplicateOwn ps = do
   where
     cfg = testCfg {deliveryWorkerDelay = 250000}
 
+-- 100 members: 965 ms
+-- 1000 members: 16395 ms
 testChannelsRelayDeliverStress :: HasCallStack => Int -> TestParams -> IO ()
 testChannelsRelayDeliverStress numMembers ps =
   withNewTestChat ps "alice" aliceProfile $ \alice -> do
     withNewTestChatOpts ps relayTestOpts "bob" bobProfile $ \bob -> do
-      withNewTestChat ps "cath" cathProfile $ \cath -> do
-        withNewTestChat ps "dan" danProfile $ \dan -> do
-          withNewTestChat ps "eve" eveProfile $ \eve -> do
-            createChannel5 "team" alice bob cath dan eve
+      (shortLink, fullLink) <- createChannel1Relay "team" alice bob
 
-            alice #> "#team hi"
-            bob <# "#team alice> hi"
-            [cath, dan, eve] *<# "#team alice> hi [>>]"
+      memberCCs <- forM [1..numMembers] $ \i -> do
+        let name = "member" <> show i
+            descr = "Member" <> show i
+            memberProfile = mkProfile (T.pack name) (T.pack descr) Nothing
+        member <- createTestChat ps testCfg testOpts name memberProfile
+        memberJoinChannel "team" bob shortLink fullLink member
+        print $ name <> " joined"
+        pure member
 
-            cath ##> "+1 #team hi"
-            cath <## "added 👍"
-            bob <# "#team cath> > alice hi"
-            bob <## "    + 👍"
-            alice <## "#team: bob forwarded a message from an unknown member, creating unknown member record cath"
-            alice <# "#team cath> > alice hi"
-            alice <## "    + 👍"
-            dan <## "#team: bob forwarded a message from an unknown member, creating unknown member record cath"
-            dan <# "#team cath> > alice hi"
-            dan <## "    + 👍"
-            eve <## "#team: bob forwarded a message from an unknown member, creating unknown member record cath"
-            eve <# "#team cath> > alice hi"
-            eve <## "    + 👍"
+      t1 <- getCurrentTime
+      print $ "starting sending to " <> show numMembers <> " members..."
+
+      alice #> "#team hi"
+      bob <# "#team alice> hi"
+      forConcurrently_ memberCCs $ \member ->
+        (dropTime <$> getTermLine' (-1) member) `shouldReturn` "#team alice> hi [>>]" -- (-1) - no timeout
+
+      t2 <- getCurrentTime
+      let diff = diffToMilliseconds $ diffUTCTime t2 t1
+      print $ "sent to " <> show numMembers <> " members in: " <> show diff <> " ms"
+
+      forConcurrently_ memberCCs $ \member -> do
+        member <// 100000
+        stopTestChat ps member