Abu Salamah bin Abdur Rahman (may Allah have mercy on him) says: I asked Sayyidah Aishah (may Allah be pleased with her) about the prayer of the Prophet (peace and blessings be upon him) in Ramadan, and she said that the Prophet (peace and blessings be upon him) did not pray more than eleven rak'ahs, in Ramadan or outside Ramadan. He (peace and blessings be upon him) would pray four rak'ahs, and do not ask about their length and beauty; then he (peace and blessings be upon him) would pray four rak'ahs, and do not ask about their length and beauty either; then he (peace and blessings be upon him) would pray three rak'ahs. Sayyidah Aishah (may Allah be pleased with her) says: I asked: O Messenger of Allah! Do you (peace and blessings be upon him) sleep before praying witr? He (peace and blessings be upon him) said: "O Aishah! My eyes sleep, but my heart stays awake."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 4673