Hello from France
Often Core i7 and Core i5 are not running at exactly the same basic speed (+ Turbo Mode is sometimes a little bit different in term of range) ...
So with about the "same" Core i5 / Core i7, ACAD 201X is running faster between 5%-10% on Core i7 !
The best purchase today (for Core i5) is of course the "old" Core i5 4570 (because the "new" Core i5 4590 is only 100 Mhz faster !)
I confirm that the best choice for ACAD 201X is : GTX 780TI (3 Gb Ram) or the cheaper GTX 780 (2 Gb Ram)
YES YES they are Gamer cards but they are very fast with ACAD 201X ...
Unfortunately the NVidia Quadro card 20xx/30xx/40xx/etc are slower ... and they are very expensive !!
I am 57 years old and I am a "Geek/Fanatic" of ACAD (1.4/2.0) since 1984/1985 ... and I am a "specialist" in Hardware and in Workstation ...
HP / Dell / Lenovo / etc sales people say every day that YOU MUST BUY a high End Workstation to run ACAD (and many other CAD program) but it's FALSE especially with ACAD 201X ...
TODAY if I have to buy a PC (Motherboard Z97) for ACAD 201X, REVIT 201X, Inventor 201X, I will buy a PC with the latest Core i7 4790K (4.0 - 4.4 Ghz - 8 Mb cache) ! + 16/24/32 Gb Fast DDR3 Ram + GTX 780TI (3 Gb Ram) + Fast SSD + Fast SATA ...
And with a GOOD fan (For example the Noctua NH-D15), I will overclock the Core i7 4790K to 4.4 - 4.8 Ghz without any problem !!
... It's a overclocking of ONLY 10% ... very easy and reliable ...
You can dore MORE but you have to switch to Water Cooling, and it's more difficult ... but you can reach 4.6 - 5.0 Mhz basic speed (+ Turbo Mode !!) ...
So Good Luck for your future PC !
Patrice ( Supporting Troops ) - Autodesk Expert Elite
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Patrice BRAUD