Wait for the next gen gpu's to be released. They're rumoured to be quite good but no one knows for sure yet. As for the cpu, you could try a i7 like the i7-4790k, its affordable but also has a good speed relative to its price
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also, regarding the ram, id recommend you stick with the same ram but just buy more of it. Assuming ur pc has 4 ram slots i would instead of replacing the 2, buy an additional 2 of the same kind and install those along side
Also, a good software on your pc to help control temperatures etc that i would recommend greatly is msi afterburner, its saved me when playing games like ark from making my pc go over 80C
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Id say just go with the same monitors, or just buy a single monitor to replace one of them. Unfortunately, im not knowledgeable in regards to monitors so i cant rlly help u there
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Also ssd's are much faster than hdd's so id invest into buying an ssd, although they have less space, they are very much worth it in my opinion.