Each time your opponent draws a card(s), place 1 Spell Counter on this card (max. 5). This card gains 500 ATK for each Spell Counter on it. During the Standby Phase of your next turn after the 5th Spell Counter is placed on this card: You can send this face-up card with 5 Spell Counters on it to the Graveyard; Special Summon 1 "Silent Magician LV8" from your hand or Deck.
In the anime, Silent Magician gains one counter for each card drawn, but in real life she gains one counter for each draw.
The real life version depends on the draw itself instead of the number of cards drawn. As a result, even if you draw multiple cards, you still only draw once for those cards, and thus she only gains 1 counter.
This makes Silent Magician LV4 useless with Silent Burning.
Literally the only Silent Magician able to make use of the card, is "Silent Magician", the newer one without LV in her name, as she has Osiris-like effect of gaining ATK based on the number of cards in your hand. Yet that's the one Konami didn't put into the game lol