diff --git a/htdocs/admin/system/perf.php b/htdocs/admin/system/perf.php
index 3e6a9df4a25..9b23dc74089 100644
--- a/htdocs/admin/system/perf.php
+++ b/htdocs/admin/system/perf.php
@@ -112,7 +112,7 @@ $test=function_exists('opcache_get_status');
 if (! $foundcache && $test)
 {
 	$foundcache++;
-	print img_picto('','tick.png').' '.$langs->trans("ZendOPCacheInstalled");  // Should be by defautl starting with PHP 5.5
+	print img_picto('','tick.png').' '.$langs->trans("ZendOPCacheInstalled");  // Should be by default starting with PHP 5.5
 	//$tmp=opcache_get_status();
 	//var_dump($tmp);
 }
@@ -376,7 +376,8 @@ jQuery(document).ready(function() {
 
 print '<br>';
 print '<strong>'.$langs->trans("HTTPCacheStaticResources").' - ';
-print $langs->trans("CacheByServer").':</strong><br>';
+print $form->textwithpicto($langs->trans("CacheByServer"), $langs->trans("CacheByServerDesc"));
+print ':</strong><br>';
 // No cahce on PHP
 //print '<div id="httpcachephpok">'.img_picto('','warning.png').' '.$langs->trans("FilesOfTypeNotCompressed",'php (.php)').'</div>';
 //print '<div id="httpcachephpko">'.img_picto('','tick.png').' '.$langs->trans("FilesOfTypeNotCached",'php (.php)').'</div>';
@@ -399,7 +400,9 @@ print $langs->trans("TestNotPossibleWithCurrentBrowsers").'<br>';
 
 // Compressions
 print '<br>';
-print '<strong>'.$langs->trans("CompressionOfResources").'</strong>: ';
+print '<strong>';
+print $form->textwithpicto($langs->trans("CompressionOfResources"), $langs->trans("CompressionOfResourcesDesc"));
+print '</strong>: ';
 //$tmp=getURLContent(DOL_URL_ROOT.'/index.php','GET');var_dump($tmp);
 print '<br>';
 // on PHP
diff --git a/htdocs/langs/en_US/admin.lang b/htdocs/langs/en_US/admin.lang
index 3662e8aca1c..1c9ac65e4b8 100644
--- a/htdocs/langs/en_US/admin.lang
+++ b/htdocs/langs/en_US/admin.lang
@@ -1353,8 +1353,10 @@ FilesOfTypeNotCached=Files of type %s are not cached by HTTP server
 FilesOfTypeCompressed=Files of type %s are compressed by HTTP server
 FilesOfTypeNotCompressed=Files of type %s are not compressed by HTTP server
 CacheByServer=Cache by server
+CacheByServerDesc=For exemple using the Apache directive "ExpiresByType image/gif A2592000"
 CacheByClient=Cache by browser
 CompressionOfResources=Compression of HTTP responses
+CompressionOfResourcesDesc=For exemple using the Apache directive "AddOutputFilterByType DEFLATE"
 TestNotPossibleWithCurrentBrowsers=Such an automatic detection is not possible with current browsers 
 DefaultValuesDesc=You can define/force here the default value you want to get when your create a new record, and/or defaut filters or sort order when your list record. 
 DefaultCreateForm=Default values for new objects