diff --git a/app/modules/prover/lib/powCluster.ts b/app/modules/prover/lib/powCluster.ts
index e61fe037726dff80801918572942bfa20250c2a4..1e1a6ad3d42afadf5c750a378426d8e7ab50df70 100644
--- a/app/modules/prover/lib/powCluster.ts
+++ b/app/modules/prover/lib/powCluster.ts
@@ -118,7 +118,7 @@ export class Master {
 
   changeConf(conf:ConfDTO) {
     this.logger.info(`Changing conf to: ${JSON.stringify(conf)} on PoW cluster`)
-    this.conf.cpu = this.conf.cpu || conf.cpu
+    this.conf.cpu = conf.cpu || this.conf.cpu
     this.conf.prefix = this.conf.prefix || conf.prefix
     this.slaves.forEach(s => {
       s.worker.send({