Ram is the most important. Trading applications usually don't need the very powerful processor, even an I3 processor is enough.
But go for 8 Gb ram. Use two 4 GB ram than one 8 GB, so that even if one down suddenly during live trading, you'll get time to replace the other one. If u r using kite and multiple pages for a long hour with various applications ideal RAM requirement is 6gb. Keep another 2 Gb extra for worst cases.
Try to find the simultaneous dual display mother board at least. For example even more than 6 yr old board like DH67BL supports dual monitor display( one DVI, one HDMI), you can use two monitor side by side.
Use 64 bit OS, window 8.1 Enterprise 64 bit is stable but lightweight.
Benq 1080p LED monitors with the latest eye care technology (search Amazon) are the low cost, but very stable. You can go for one bigger monitor too like 27 inches. Probably cost is only about 14-15k.
It's always good for day trading if u can view all your required application side by side preferably with multi-monitor desktop.
Try to spend good money on the desktop, a dual monitor desktop is a must for trading. Save some money from processor price. I3 is enough as u r using few web application like kite, nest/now and amibroker;
not the high-end application like Ninja Trader, Traders Works station, MotiveWave etc(I can guess what u are using
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I assume your budget is moderate, as you are asking for advice. So, tried according to this. If u have some extra money after decent investment on motherboard and monitor go for I5. But before that, if u want speed go for SSD Drive(your pc performance will increase heavily with SSD drive even with a moderate processor, but min requirement is I3) . And a good Power Supply is the must.
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If your budget is big go for 32 Gb Ram(16+16), Gaming Mother Board(Asus) with Ultra HD 4K multiple monitor display and 8th gen Cpu.