diff --git a/lib/components/chat-mention-provider.react.js b/lib/components/chat-mention-provider.react.js
--- a/lib/components/chat-mention-provider.react.js
+++ b/lib/components/chat-mention-provider.react.js
@@ -176,13 +176,22 @@
   };
 }
 
+// Without allAtOnce, useChatMentionCandidatesObjAndUtils is very expensive.
+// useResolvedThreadInfosObj 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 useResolvedThreadInfosObjOptions = { allAtOnce: true };
+
 function useChatMentionCandidatesObjAndUtils(): {
   chatMentionCandidatesObj: ChatMentionCandidatesObj,
   resolvedThreadInfos: ChatMentionCandidates,
   communityThreadIDForGenesisThreads: { +[id: string]: string },
 } {
   const threadInfos = useSelector(threadInfoSelector);
-  const resolvedThreadInfos = useResolvedThreadInfosObj(threadInfos);
+  const resolvedThreadInfos = useResolvedThreadInfosObj(
+    threadInfos,
+    useResolvedThreadInfosObjOptions,
+  );
   const { chatMentionCandidatesObj, communityThreadIDForGenesisThreads } =
     React.useMemo(
       () => getChatMentionCandidates(resolvedThreadInfos),
diff --git a/lib/utils/entity-helpers.js b/lib/utils/entity-helpers.js
--- a/lib/utils/entity-helpers.js
+++ b/lib/utils/entity-helpers.js
@@ -8,17 +8,19 @@
   useENSNamesForEntityText,
   entityTextToRawString,
 } from './entity-text.js';
+import type { UseENSNamesOptions } from '../hooks/ens-cache.js';
 import type { ThreadInfo, ResolvedThreadInfo } from '../types/thread-types.js';
 import { values } from '../utils/objects.js';
 
 function useResolvedThreadInfos(
   threadInfos: $ReadOnlyArray<ThreadInfo>,
+  options?: ?UseENSNamesOptions,
 ): $ReadOnlyArray<ResolvedThreadInfo> {
   const entityText = React.useMemo(
     () => threadInfos.map(threadInfo => threadInfo.uiName),
     [threadInfos],
   );
-  const withENSNames = useENSNamesForEntityText(entityText);
+  const withENSNames = useENSNamesForEntityText(entityText, options);
   invariant(
     withENSNames,
     'useENSNamesForEntityText only returns falsey when passed falsey',
@@ -76,14 +78,18 @@
   }, [threadInfos, withENSNames]);
 }
 
-function useResolvedThreadInfosObj(threadInfosObj: {
-  +[id: string]: ThreadInfo,
-}): { +[id: string]: ResolvedThreadInfo } {
+function useResolvedThreadInfosObj(
+  threadInfosObj: { +[id: string]: ThreadInfo },
+  options?: ?UseENSNamesOptions,
+): { +[id: string]: ResolvedThreadInfo } {
   const threadInfosArray = React.useMemo(
     () => values(threadInfosObj),
     [threadInfosObj],
   );
-  const resolvedThreadInfosArray = useResolvedThreadInfos(threadInfosArray);
+  const resolvedThreadInfosArray = useResolvedThreadInfos(
+    threadInfosArray,
+    options,
+  );
   return React.useMemo(() => {
     const obj = {};
     for (const resolvedThreadInfo of resolvedThreadInfosArray) {
diff --git a/lib/utils/entity-text.js b/lib/utils/entity-text.js
--- a/lib/utils/entity-text.js
+++ b/lib/utils/entity-text.js
@@ -6,7 +6,7 @@
 
 import type { GetENSNames } from './ens-helpers.js';
 import { tID, tShape, tString } from './validation-utils.js';
-import { useENSNames } from '../hooks/ens-cache.js';
+import { useENSNames, type UseENSNamesOptions } from '../hooks/ens-cache.js';
 import { threadNoun } from '../shared/thread-utils.js';
 import { stringForUser } from '../shared/user-utils.js';
 import {
@@ -533,12 +533,15 @@
     .filter(Boolean);
 }
 
-function useENSNamesForEntityText(entityText: ?EntityText): ?EntityText {
+function useENSNamesForEntityText(
+  entityText: ?EntityText,
+  options?: ?UseENSNamesOptions,
+): ?EntityText {
   const allObjects = React.useMemo(
     () => (entityText ? entityTextToObjects(entityText) : []),
     [entityText],
   );
-  const objectsWithENSNames = useENSNames(allObjects);
+  const objectsWithENSNames = useENSNames(allObjects, options);
   return React.useMemo(
     () =>
       entityText ? entityTextFromObjects(objectsWithENSNames) : entityText,