diff --git a/Source/Modules/IMEModules/mgrPrefs.swift b/Source/Modules/IMEModules/mgrPrefs.swift
index 1ff64f84..5257c6c2 100644
--- a/Source/Modules/IMEModules/mgrPrefs.swift
+++ b/Source/Modules/IMEModules/mgrPrefs.swift
@@ -82,8 +82,8 @@ private let kMaxCandidateListTextSize: CGFloat = 196
 // will start to sputter beyond 12 such is the algorithmatic complexity
 // of the Viterbi algorithm used in the builder library (at O(N^2))
 private let kDefaultComposingBufferSize = 20
-private let kMinComposingBufferSize = 4
-private let kMaxComposingBufferSize = 30
+private let kMinComposingBufferSize = 10
+private let kMaxComposingBufferSize = 40
 
 private let kDefaultKeys = "123456789"