Hi Chintan,
I only agree with you partially. 'Intel process architecture is more efficient...' Yeah some softwares like AutoCAD, etc. are (or used to be) designed- to work better on Intel processors. But lately, AMD's Ryzen series is getting popular for the same and also for the Price-performance stuff.
And I guess GPU's are more or less supportive in graphics demand rather than the CPU. And if I'm right then the number of cores and processing speed is the one that matters. That's why workstation CPU's & GPU's as well have more cores and Graphics RAM & clock-speed. Finally, the deciding factor will be your requirements & budget. Earlier Intel used to lead market but that era has ended, now both Intel & AMD compete equally.
And as far as ECC RAM goes- I would like to say they are useful only in real-critical applications where data accuracy is really important like: Rocket launch systems, scientific and medical systems etc. But some people are trying to use them anyways. Both Intel and AMD processors (and others) supports ECC function from a long time. In-fact, ECC has been openly supported by AMD, whilst Intel limits it to High-end Xeon H/W. So, in majority its the motherboards that decides if you can use ECC or not. Such ECC-RAM systems are always heavy on pocket, so one should really look up before spending, if s/he really needs that much accuracy.
If I'm missing on something, please share! :)
EDIT: If someone needs more calculation stuff, s/he definitely needs to look for best CPU in the budget. And GPU if that someone needs to process more of a graphics stuff. Additionally, one should also check the program(s) s/he will be using which sets the requirements for CPU or GPU, etc.