Sheldon thinks of himself as more superior and more intellectual than Einstein.

Below is an quote from Wikia, about the episode "The Einstein Approximation" (S3, E14):[1]

A few hours afterwards, Leonard and Penny are asleep again, but Sheldon wakes them up and tells them that his solution to his math problem is working in a menial job, much like how Albert Einstein did when he was working at the Patent Office in Switzerland and discovered special relativity.

With this statement made by Sheldon, one can assume he thinks the revelation of special relativity was a "no-biggie" and comparable with something in Sheldons daily life. He has also, according to a reddit comment,[2] said that "relativity would have been obvious to him".

One could perhaps view it as though ´"Sheldon decided to seek a mind-numbing vocation (bussing tables at the Cheesecake Factory) because he felt that Einstein's mind-numbing job at the patent office was partially responsible for his breakthroughs",[3] but what would be the fun in that. We all know Sheldon, and he is, to be honest, very condesending. In a good way :P

Another thing to consider is that Einstein has an IQ level of (between) 160 (and 190)[4] and Sheldon Cooper has claimed to have an IQ level of 187,[5] making him smarter than Einstein (if measured with IQ, and assuming Einstain only had 160).[6]

And as Nick Kasparie says in his answer, he does hold another smart scientist at high regards; Stephen Hawking.[7]

(Sorry for not using reliable sources, but we are talking about a fictional character, some users intepretations are as good as another's.)

Footnotes

[1] The Einstein Approximation

[2] https://www.reddit.com/r/bigbang...

[3] Page on reddit.com

[4] http://listovative.com/top-12-pe...

[5] Utsav Roy's answer to Why Dr Sheldon Cooper is not as successful as he should have been?

[6] Who is smarter albert Einstein or Sheldon cooper?

[7] Nick Kasparie's answer to What does Sheldon Cooper think of Einstein?