diff --git a/src/libraries/Common/tests/TestUtilities/System/PlatformDetection.cs b/src/libraries/Common/tests/TestUtilities/System/PlatformDetection.cs
index a33f7a09f2df2c..31fe9553f54278 100644
--- a/src/libraries/Common/tests/TestUtilities/System/PlatformDetection.cs
+++ b/src/libraries/Common/tests/TestUtilities/System/PlatformDetection.cs
@@ -106,9 +106,20 @@ public static bool IsPrivilegedProcess
         public static bool IsReleaseLibrary(Assembly assembly) => !IsDebuggable(assembly);
         public static bool IsDebugLibrary(Assembly assembly) => IsDebuggable(assembly);
 
-        // For use as needed on tests that time out when run on a Debug runtime.
+        // For use as needed on tests that time out when run on a Debug or Checked runtime.
         // Not relevant for timeouts on external activities, such as network timeouts.
-        public static int SlowRuntimeTimeoutModifier = (PlatformDetection.IsDebugRuntime ? 5 : 1);
+        public static int SlowRuntimeTimeoutModifier
+        {
+            get
+            {
+                if (IsReleaseRuntime)
+                    return 1;
+                if (IsRiscV64Process)
+                    return IsDebugRuntime? 10 : 2;
+                else
+                    return IsDebugRuntime? 5 : 1;
+            }
+        }
 
         public static bool IsCaseInsensitiveOS => IsWindows || IsOSX || IsMacCatalyst;
         public static bool IsCaseSensitiveOS => !IsCaseInsensitiveOS;