The IITs have their own class and caste system. The class system is one of grades, the point that has been well-illustrated by the book "Five-point someone". Everyone in campus is a something-pointer, and this classification gets established right at the end of semester II and chases one all the way to semester VIII (and beyond, sadly).
There are juntas who slide down from a 9-pointer to an 8-something, there are those who that crash and burn all the way to the dreaded 6-somethings. Less frequently, we would hear about the upwardly mobile as well; the rare "fighters" who travel in the opposite direction. This group undergoes the same acceptance problems as any aspiring class but gains recognition once 2 semesters go by.
In every branch there are 9-pointers to 6-pointers and beyond. In many ways, local social standing and preconceptions are built pretty much around this number. One of the main planks of Alpha-male-dom in campus is the number attached after (or before) your name. The Chetan Bagat novel actually captures this very well.
The caste system in IITs is one based on branch or department. Depending on the craze and frenzy of the times, the departments are placed in some order. Computer Science is usually on top, followed by electrical, mech, chem and then the rest(see how patronizing that was. Caste usually operates like that).
People earn(!) branch changes at the end of semester II if they are in the top x% of the overall batch or some such norm; but barring this naturalization, there is no way of changing your caste (branch). People can choose to move to "lower" branches without any CGPA cut-off at the end of semester II, although political correctness usually demands that this not be called a "branch slide".
Even the most broad-minded and politically correct juntas usually accept the caste/class norms and this is what keeps these norms from disappearing. For any class/caste system to really gain acceptance, the so-called "lower" class/caste should subconsciously accept the hierarchy. The group dynamics in IITs ensure that this happens smoothly.
So, how does one compare an elec 7-pointer with a 9-pointer from a "lower" branch? Thats a tricky one. Both will argue that they are superior to the other. But in many cases, if you are sufficiently lower in caste, the class ceases to count. To give an example, a mech 9-pointer can have a better standing than an elec 7-pointer, but there is a good chance that the meta 9-pointer cannot compete.
I had this memorable conversation with my classmate who was (is) an electrical engineer. And who (like yours truly) was designated low class by semester III (we were both 7 pointers). There was this 4th year student from our hostel who was in the top few in his branch and felt he had done enough academically to impart gyaan to students two years his junior. The only problem was that he was a topper in metallurgical engineering. And meta is a low-caste branch, if you know what I mean.
My friend patiently listened to said pompous git for about 3 minutes, waited for the guy to leave and then said "Meta-****** have started speaking to me about academics. ****** . ***^&%^*.. I would effing be an elec 5-pointer than be the branch record holder in that ***'s branch. Somebody should tell that ***** that he can shove his advice up his ********. If he can clear the electronics paper in my effing branch without getting his *** whipped, I will listen to the **** for more than effing 3 minutes. *****.
Caste overrides class here.
We have parallels of the caste/class demarcation in many different fields. Academic background/Job is one such. Essentially, one aspect that cannot be easily changed along with one that can be improved upon together combining to count for social standing is a caste/class system
Grade/branch in IITs
Academic background/ Job performance
Beauty quotient of wife/ wealth
Inherited wealth/ income generated
This is probably the reason why the caste system is more odious than the class one. Because you can still alter your class - through smarts, luck or perseverance. But if you are a meta dude, there is no way in hell you can give gyaan to Computer Science graduates and hope to be listened to. And that somehow grates more.
P.S: On a side note, that meta dude was a muppet. Pompous non-achiever if ever there was one. :)