diff --git a/src/platforms/GitHub/API.ts b/src/platforms/GitHub/API.ts
index 29f97cf..e9df774 100644
--- a/src/platforms/GitHub/API.ts
+++ b/src/platforms/GitHub/API.ts
@@ -96,7 +96,7 @@ export async function getTreeData(
   return await request(url, { accessToken })
 }
 
-export async function getPullData(
+export async function getPullRequest(
   userName: string,
   repoName: string,
   pullId: string,
diff --git a/src/platforms/GitHub/DOMHelper.ts b/src/platforms/GitHub/DOMHelper.ts
index adb2a81..9cf94a3 100644
--- a/src/platforms/GitHub/DOMHelper.ts
+++ b/src/platforms/GitHub/DOMHelper.ts
@@ -1,7 +1,7 @@
 import { raiseError } from 'analytics'
 import { Clippy, ClippyClassName } from 'components/Clippy'
 import * as React from 'react'
-import { $, formatClass } from 'utils/DOMHelper'
+import { $, formatClass, parseIntFromElement } from 'utils/DOMHelper'
 import { renderReact, run } from 'utils/general'
 import { CopyFileButton, copyFileButtonClassName } from './CopyFileButton'
 
@@ -32,7 +32,7 @@ export function isInCodePage() {
 }
 
 export function isInPullFilesPage() {
-  return $('#files_tab_counter')
+  return $('.tabnav-tab.selected #files_tab_counter')
 }
 
 export function getIssueTitle() {
@@ -277,3 +277,17 @@ export function isNativePRFileTreeShown() {
 export function selectEnterpriseStatHeader() {
   return $('.stats-ui-enabled .server-stats')
 }
+
+export function getPullRequestFilesCount() {
+  return $('#files_tab_counter', parseIntFromElement)
+}
+
+export function getPRDiffTotalStat() {
+  const [added, removed] = [$('#diffstat .color-fg-success'), $('#diffstat .color-fg-danger')].map(
+    e => (e ? parseIntFromElement(e) : null),
+  )
+  return {
+    added,
+    removed,
+  }
+}
diff --git a/src/platforms/GitHub/getPullRequestTreeData.ts b/src/platforms/GitHub/getPullRequestTreeData.ts
index 5c3fe47..de71c98 100644
--- a/src/platforms/GitHub/getPullRequestTreeData.ts
+++ b/src/platforms/GitHub/getPullRequestTreeData.ts
@@ -1,24 +1,42 @@
 import { formatHash } from 'utils/general'
 import * as API from './API'
-import { isInPullFilesPage } from './DOMHelper'
+import { getPRDiffTotalStat, getPullRequestFilesCount, isInPullFilesPage } from './DOMHelper'
 import { processTree } from './index'
 import { getCommentsMap } from './utils'
 
+function checkShouldSafeGet() {
+  const FAST_GET_DIFF_THRESHOLD = 10000
+  const FAST_GET_FILES_THRESHOLD = 200
+  const { added, removed } = getPRDiffTotalStat()
+  const filesCount = getPullRequestFilesCount()
+  return (
+    added === null ||
+    removed === null ||
+    filesCount === null ||
+    (added + removed < FAST_GET_DIFF_THRESHOLD && filesCount < FAST_GET_FILES_THRESHOLD)
+  )
+}
+
 export async function getPullRequestTreeData(
   metaData: Pick<MetaData, 'userName' | 'repoName' | 'branchName'>,
   pullId: string,
   accessToken?: string,
-  useSafeRequest = true,
+  shouldSafeGet = checkShouldSafeGet(),
 ) {
   const { userName, repoName } = metaData
   const [treeData, commentData] = await Promise.all([
-    useSafeRequest
+    shouldSafeGet
       ? safeGetPullRequestTreeData(metaData, pullId, accessToken)
       : fastGetPullRequestTreeData(metaData, pullId, accessToken),
     API.getPullComments(userName, repoName, pullId, accessToken),
   ])
 
-  const docs = await API.getPullPageDocuments(userName, repoName, pullId, isInPullFilesPage() ? document : undefined)
+  const docs = await API.getPullPageDocuments(
+    userName,
+    repoName,
+    pullId,
+    isInPullFilesPage() ? document : undefined,
+  )
   // query all elements at once to make getFileElementHash run faster
   const elementsHavePath = docs.map(doc => doc.querySelectorAll(`[data-path]`))
   const getFileElementHash = (path: string) => {
@@ -87,20 +105,17 @@ async function fastGetPullRequestTreeData(
   pullId: string,
   accessToken?: string,
 ) {
-  const [pullData, treeData] = await Promise.all([
-    API.getPullData(userName, repoName, pullId, accessToken),
-    API.getPullTreeData(
-      userName,
-      repoName,
-      pullId,
-      1,
-      GITHUB_API_RESPONSE_MAX_SIZE_PER_PAGE,
-      accessToken,
-    ),
-  ])
+  const treeData = await API.getPullTreeData(
+    userName,
+    repoName,
+    pullId,
+    1,
+    GITHUB_API_RESPONSE_MAX_SIZE_PER_PAGE,
+    accessToken,
+  )
 
-  const count = pullData.changed_files
-  if (treeData.length < count) {
+  const count = getPullRequestFilesCount()
+  if (count !== null && treeData.length < count) {
     let page = 1
     const restPages = []
     while (page * GITHUB_API_RESPONSE_MAX_SIZE_PER_PAGE < count) {
diff --git a/src/utils/DOMHelper.ts b/src/utils/DOMHelper.ts
index be14b24..cd8383e 100644
--- a/src/utils/DOMHelper.ts
+++ b/src/utils/DOMHelper.ts
@@ -154,3 +154,7 @@ export function formatID(id: string) {
 export function formatClass(className: string) {
   return `.${className}`
 }
+
+export function parseIntFromElement(e: HTMLElement): number {
+  return parseInt((e.innerText || '').replace(/[^0-9]/g, ''))
+}