diff --git a/lib/selectors/nav-selectors.js b/lib/selectors/nav-selectors.js
--- a/lib/selectors/nav-selectors.js
+++ b/lib/selectors/nav-selectors.js
@@ -3,7 +3,7 @@
 import * as React from 'react';
 import { createSelector } from 'reselect';
 
-import { useENSNames } from '../hooks/ens-cache.js';
+import { ENSCacheContext } from '../components/ens-cache-provider.react.js';
 import SearchIndex from '../shared/search-index.js';
 import { memberHasAdminPowers } from '../shared/thread-utils.js';
 import type { Platform } from '../types/device-types.js';
@@ -16,6 +16,7 @@
 import type { BaseAppState } from '../types/redux-types.js';
 import type { RawThreadInfo, ThreadInfo } from '../types/thread-types.js';
 import { getConfig } from '../utils/config.js';
+import { getENSNames } from '../utils/ens-helpers.js';
 import { values } from '../utils/objects.js';
 import { useSelector } from '../utils/redux-utils.js';
 
@@ -100,14 +101,34 @@
     return [...allMembersOfAllThreads.values()];
   }, [threadInfos, userInfos, viewerID]);
 
-  const nonViewerMembersWithENSNames = useENSNames(nonViewerMembers);
+  const cacheContext = React.useContext(ENSCacheContext);
+  const { ensCache } = cacheContext;
+
+  // We avoid using useENSNames here because the SearchIndex memo below is very
+  // expensive. useENSNames would trigger its recalculation for each ENS name as
+  // it streams in, but we would prefer to trigger its recaculation just once
+  // for every update of the underlying Redux data.
+  const [nonViewerMembersWithENSNames, setNonViewerMembersWithENSNames] =
+    React.useState();
+  React.useEffect(() => {
+    if (!ensCache) {
+      return;
+    }
+    (async () => {
+      const withENSNames = await getENSNames(ensCache, nonViewerMembers);
+      setNonViewerMembersWithENSNames(withENSNames);
+    })();
+  }, [ensCache, nonViewerMembers]);
+
+  const resolvedNonViewerMembers =
+    nonViewerMembersWithENSNames ?? nonViewerMembers;
   const memberMap = React.useMemo(() => {
     const result = new Map();
-    for (const userInfo of nonViewerMembersWithENSNames) {
+    for (const userInfo of resolvedNonViewerMembers) {
       result.set(userInfo.id, userInfo);
     }
     return result;
-  }, [nonViewerMembersWithENSNames]);
+  }, [resolvedNonViewerMembers]);
 
   return React.useMemo(() => {
     const searchIndex = new SearchIndex();