diff --git a/classes/range.js b/classes/range.js
index a791d912..29598bff 100644
--- a/classes/range.js
+++ b/classes/range.js
@@ -81,8 +81,8 @@ class Range {
 
     // memoize range parsing for performance.
     // this is a very hot path, and fully deterministic.
-    const memoOpts = Object.keys(this.options).join(',')
-    const memoKey = `parseRange:${memoOpts}:${range}`
+    const memoOpts = buildMemoKeyFromOptions(this.options)
+    const memoKey = memoOpts + ':' + range
     const cached = cache.get(memoKey)
     if (cached) {
       return cached
@@ -190,6 +190,35 @@ class Range {
     return false
   }
 }
+
+function buildMemoKeyFromOptions (options) {
+  if (options.includePrerelease === true) {
+    if (options.loose === true && options.rtl === true) {
+      return '1'
+    }
+
+    if (options.loose === true) {
+      return '2'
+    }
+
+    if (options.rtl === true) {
+      return '3'
+    }
+
+    return '4'
+  } else if (options.loose === true) {
+    if (options.rtl === true) {
+      return '5'
+    }
+
+    return '6'
+  } else if (options.rtl === true) {
+    return '7'
+  } else {
+    return '8'
+  }
+}
+
 module.exports = Range
 
 const LRU = require('lru-cache')