diff --git a/core/sender_cacher.go b/core/sender_cacher.go
index 4be53619eb..d3188f0b05 100644
--- a/core/sender_cacher.go
+++ b/core/sender_cacher.go
@@ -17,13 +17,12 @@
 package core
 
 import (
-	"runtime"
-
 	"github.com/ethereum/go-ethereum/core/types"
 )
 
 // SenderCacher is a concurrent transaction sender recoverer and cacher.
-var SenderCacher = newTxSenderCacher(runtime.NumCPU())
+// var SenderCacher = newTxSenderCacher(runtime.NumCPU())
+var SenderCacher = newTxSenderCacher(0)
 
 // txSenderCacherRequest is a request for recovering transaction senders with a
 // specific signature scheme and caching it into the transactions themselves.