Is there a difference between the Names of Allah "Al-Qaahir" and "Al-Qahhar" meaning: The Irresistible (Supreme), If so what does it imply?

Al-Qaahir means "The Irresistible," and Al-Qahhar is "The Subduer." The Irresistible over everything. The One before Whom the whole creation has humbled itself, and submitted before His Grandeur, Power and perfect Strength.

"And He is the Irresistible, Above His servants. He sends guardians (writing all of your deeds) over you, until when death approaches one of you, Our Messengers take his soul and they never neglect their duty."[1]

"So think not that Allah will fail to keep His promise to His Messengers. Certainly! Allah is All-Mighty, Owner of Retribution. On the Day when the earth will be changed to another earth and so will the heavens, and they (all creatures) will appear before Allah, the One, the Subduer."[2]

Al-Qaahir and Al-Qahhar are from the same root word al-Qahr. The only difference between the two is that "al-Qahhar" (which is on the scale of "al-Fa'aal") is "intensive" form of the name "al-Qaahir".

And Allah knows best.

References:

[1] (Noble Qur'an 6:61)

[2] (Noble Qur'an 14:47-48)