diff --git a/inst/atime/tests.R b/.ci/atime/tests.R
similarity index 86%
rename from inst/atime/tests.R
rename to .ci/atime/tests.R
index 19c1b27a8..c5d2e3f25 100644
--- a/inst/atime/tests.R
+++ b/.ci/atime/tests.R
@@ -74,7 +74,7 @@ pkg.edit.fun = function(old.Package, new.Package, sha, new.pkg.path) {
 test.list <- list(
   # Performance regression discussed in: https://github.com/Rdatatable/data.table/issues/4311
   # Fixed in: https://github.com/Rdatatable/data.table/pull/4440
-  "Test regression fixed in #4440" = list(
+  "shallow regression fixed in #4440" = list(
     pkg.edit.fun = pkg.edit.fun,
     N = 10^seq(3,8),
     setup = quote({
@@ -90,7 +90,7 @@ test.list <- list(
   # Test based on: https://github.com/Rdatatable/data.table/issues/5424
   # Performance regression introduced from a commit in: https://github.com/Rdatatable/data.table/pull/4491
   # Fixed in: https://github.com/Rdatatable/data.table/pull/5463
-  "Test regression fixed in #5463" = list(
+  "memrecycle regression fixed in #5463" = list(
     pkg.edit.fun = pkg.edit.fun,
     N = 10^seq(3, 8),
     setup = quote({
@@ -105,6 +105,22 @@ test.list <- list(
     expr = quote(data.table:::`[.data.table`(dt_mod, , N := .N, by = g)),
     Before = "be2f72e6f5c90622fe72e1c315ca05769a9dc854", # Parent of the regression causing commit (https://github.com/Rdatatable/data.table/commit/e793f53466d99f86e70fc2611b708ae8c601a451) in the PR that introduced the issue (https://github.com/Rdatatable/data.table/pull/4491/commits)
     Regression = "e793f53466d99f86e70fc2611b708ae8c601a451", # Commit responsible for regression in the PR that introduced the issue (https://github.com/Rdatatable/data.table/pull/4491/commits)
-    Fixed = "58409197426ced4714af842650b0cc3b9e2cb842") # Last commit in the PR that fixed the regression (https://github.com/Rdatatable/data.table/pull/5463/commits)
+    Fixed = "58409197426ced4714af842650b0cc3b9e2cb842"), # Last commit in the PR that fixed the regression (https://github.com/Rdatatable/data.table/pull/5463/commits)
+
+  # Issue reported in: https://github.com/Rdatatable/data.table/issues/5426
+  # To be fixed in: https://github.com/Rdatatable/data.table/pull/5427
+  "setDT improved in #5427" = list(
+  pkg.edit.fun = pkg.edit.fun,
+  N = 10^seq(1, 7),
+  setup = quote({
+    L <- replicate(N, 1, simplify = FALSE)
+    setDT(L)
+  }),
+  expr = quote({
+    data.table:::setattr(L, "class", NULL)
+    data.table:::setDT(L)
+  }),
+  Slow = "c4a2085e35689a108d67dacb2f8261e4964d7e12", # Parent of the first commit in the PR that fixes the issue (https://github.com/Rdatatable/data.table/commit/7cc4da4c1c8e568f655ab5167922dcdb75953801)
+  Fast = "1872f473b20fdcddc5c1b35d79fe9229cd9a1d15") # Last commit in the PR that fixes the issue (https://github.com/Rdatatable/data.table/pull/5427/commits)
 )
 # nolint end: undesirable_operator_linter.
diff --git a/.github/workflows/performance-tests.yml b/.github/workflows/performance-tests.yml
index 2fc3a76f5..cb30e7625 100644
--- a/.github/workflows/performance-tests.yml
+++ b/.github/workflows/performance-tests.yml
@@ -10,7 +10,8 @@ on:
       - synchronize
     paths:
       - 'R/**'
-      - 'src/**'       
+      - 'src/**'
+      - '.ci/atime/**'
 
 jobs:
   comment:
@@ -20,4 +21,4 @@ jobs:
       GITHUB_PAT: ${{ secrets.GITHUB_TOKEN }}
       repo_token: ${{ secrets.GITHUB_TOKEN }}
     steps:
-      - uses: Anirban166/Autocomment-atime-results@v1.1.6
+      - uses: Anirban166/Autocomment-atime-results@v1.2.0