diff --git a/caches.go b/caches.go
index 280f5445..524ec410 100644
--- a/caches.go
+++ b/caches.go
@@ -20,37 +20,31 @@ import (
 type clientRegionCache struct {
 	m sync.RWMutex
 
-	regions map[hrpc.RegionClient]map[hrpc.RegionInfo]struct{}
+	regionClients map[string]hrpc.RegionClient
+	regions       map[string]map[hrpc.RegionInfo]struct{}
 }
 
 // put caches client and associates a region with it. Returns a client that is in cache.
-// TODO: obvious place for optimization (use map with address as key to lookup exisiting clients)
 func (rcc *clientRegionCache) put(c hrpc.RegionClient, r hrpc.RegionInfo) hrpc.RegionClient {
 	rcc.m.Lock()
-	for existingClient, regions := range rcc.regions {
-		// check if client already exists, checking by host and port
-		// because concurrent callers might try to put the same client
-		if c.Addr() == existingClient.Addr() {
-			// check client already knows about the region, checking
-			// by pointer is enough because we make sure that there are
-			// no regions with the same name around
-			if _, ok := regions[r]; !ok {
-				regions[r] = struct{}{}
-			}
-			rcc.m.Unlock()
-
-			log.WithFields(log.Fields{
-				"existingClient": existingClient,
-				"client":         c,
-			}).Debug("region client is already in client's cache")
-			return existingClient
+	if regions, ok := rcc.regions[c.Addr()]; ok {
+		if _, ok := regions[r]; !ok {
+			regions[r] = struct{}{}
 		}
+		existingClient := rcc.regionClients[c.Addr()]
+		rcc.m.Unlock()
+
+		log.WithFields(log.Fields{
+			"existingClient": existingClient,
+			"client":         c,
+		}).Debug("region client is already in client's cache")
+		return existingClient
 	}
 
 	// no such client yet
-	rcc.regions[c] = map[hrpc.RegionInfo]struct{}{r: struct{}{}}
+	rcc.regionClients[c.Addr()] = c
+	rcc.regions[c.Addr()] = map[hrpc.RegionInfo]struct{}{r: struct{}{}}
 	rcc.m.Unlock()
-
 	log.WithField("client", c).Info("added new region client")
 	return c
 }
@@ -60,7 +54,7 @@ func (rcc *clientRegionCache) del(r hrpc.RegionInfo) {
 	c := r.Client()
 	if c != nil {
 		r.SetClient(nil)
-		regions := rcc.regions[c]
+		regions := rcc.regions[c.Addr()]
 		delete(regions, r)
 	}
 	rcc.m.Unlock()
@@ -68,11 +62,12 @@ func (rcc *clientRegionCache) del(r hrpc.RegionInfo) {
 
 func (rcc *clientRegionCache) closeAll() {
 	rcc.m.Lock()
-	for client, regions := range rcc.regions {
+	for cAddr, regions := range rcc.regions {
 		for region := range regions {
 			region.MarkUnavailable()
 			region.SetClient(nil)
 		}
+		client := rcc.regionClients[cAddr]
 		client.Close()
 	}
 	rcc.m.Unlock()
@@ -80,8 +75,8 @@ func (rcc *clientRegionCache) closeAll() {
 
 func (rcc *clientRegionCache) clientDown(c hrpc.RegionClient) map[hrpc.RegionInfo]struct{} {
 	rcc.m.Lock()
-	downregions, ok := rcc.regions[c]
-	delete(rcc.regions, c)
+	downregions, ok := rcc.regions[c.Addr()]
+	delete(rcc.regions, c.Addr())
 	rcc.m.Unlock()
 
 	if ok {
@@ -90,17 +85,13 @@ func (rcc *clientRegionCache) clientDown(c hrpc.RegionClient) map[hrpc.RegionInf
 	return downregions
 }
 
-// TODO: obvious place for optimization (use map with address as key to lookup exisiting clients)
 func (rcc *clientRegionCache) checkForClient(addr string) hrpc.RegionClient {
 	rcc.m.RLock()
-
-	for client := range rcc.regions {
-		if client.Addr() == addr {
-			rcc.m.RUnlock()
-			return client
-		}
+	if _, ok := rcc.regions[addr]; ok {
+		client := rcc.regionClients[addr]
+		rcc.m.RUnlock()
+		return client
 	}
-
 	rcc.m.RUnlock()
 	return nil
 }
diff --git a/client.go b/client.go
index 6f54259d..51cd97df 100644
--- a/client.go
+++ b/client.go
@@ -116,7 +116,8 @@ func newClient(zkquorum string, options ...Option) *client {
 		clientType: standardClient,
 		regions:    keyRegionCache{regions: b.TreeNew(region.CompareGeneric)},
 		clients: clientRegionCache{
-			regions: make(map[hrpc.RegionClient]map[hrpc.RegionInfo]struct{}),
+			regionClients: make(map[string]hrpc.RegionClient),
+			regions:       make(map[string]map[hrpc.RegionInfo]struct{}),
 		},
 		rpcQueueSize:  defaultRPCQueueSize,
 		flushInterval: defaultFlushInterval,
diff --git a/metacache_test.go b/metacache_test.go
index b413435b..6de530f3 100644
--- a/metacache_test.go
+++ b/metacache_test.go
@@ -649,9 +649,9 @@ func TestClientCachePut(t *testing.T) {
 		t.Errorf("Expected 1 client in cache, got %d", len(client.clients.regions))
 	}
 
-	if len(client.clients.regions[regClient]) != 1 {
+	if len(client.clients.regions[regClient.Addr()]) != 1 {
 		t.Errorf("Expected 1 region for client in cache, got %d",
-			len(client.clients.regions[regClient]))
+			len(client.clients.regions[regClient.Addr()]))
 	}
 
 	// try putting client with the same host port
@@ -676,8 +676,8 @@ func TestClientCachePut(t *testing.T) {
 		t.Errorf("Expected 1 client in cache, got %d", len(client.clients.regions))
 	}
 
-	if len(client.clients.regions[regClient]) != 2 {
+	if len(client.clients.regions[regClient.Addr()]) != 2 {
 		t.Errorf("Expected 2 regions for client in cache, got %d",
-			len(client.clients.regions[regClient]))
+			len(client.clients.regions[regClient.Addr()]))
 	}
 }