Portugal international Pepe, 34, said Real Madrid supporters do not compare to fans from Turkish champions Besiktas.
Former Real Madrid defender Pepe described the LaLiga club's fans as unenthusiastic, rubbishing the atmosphere at the Santiago Bernabeu compared to his new home in Turkey.
Besiktas veteran Pepe enjoyed a trophy-laden career in the Spanish capital, helping Madrid to three LaLiga titles, as many Champions League crows and two Club World Cup medals among more.
Now playing for Turkish giants Besiktas, the 34-year-old said Madrid supporters – who have booed Cristiano Ronaldo, Gareth Bale and Karim Benzema this season – do not compare to fans from the Istanbul-based club.
"Perhaps Real Madrid fans won't like me saying this but they say Real Madrid fans transmit enthusiasm but I don't think they do. That's not the reality," Portugal international Pepe told beIN Sports.
"The Besiktas fans are very passionate. When you go out onto the pitch the noise coming from the stands always hits you."
Pepe added: "The atmosphere at Besiktas is very different to at Real Madrid. In Turkey people really love sport, they only think about football.
"After games, we can hear the noise of the supporters until the early hours of the morning."
Besiktas are third in the Turkish Super Lig, five points behind leaders Galatasaray,
while they are top of their Champions League group
Spanish and European champions Madrid, meanwhile, are eight points adrift of LaLiga pacesetters Barcelona.