What's wrong with memcached on Prestashop?

Question

memcached

There is memcached on the server, but when I try to enable it (by setting the port and 127.0.0.1) in prestashop I get the message:

"to use Memcached, you must install the Memcache PECL exstension on your server"
but the thing is that I have this beast installed . here is a snippet from php info

when i run a simple script to check

<?php
$mc = new Memcached();
$mc->addServer("127.0.0.1", 11211);
 
$result = $mc->get("test_key");
 
if($result) {
  echo $result;
} else {
  echo "No data on Cache. Please refresh page pressing F5";
  $mc->set("test_key", "test data pulled from Cache!") or die ("Failed to save data at Memcached server");
}
?>

all OK. I see - test data pulled from Cache, however, when trying to activate it in prestashop, there are again messages about the missing php module.
Where to dig?
Thank you.

Answer 1

php.net/manual/en/memcache.installation.php
stackoverflow.com/questions/1825256/memcache-vs-me...