I have an old system with Intel LGA-775 processor with NVidia GTX460, Creative Titanium HD, 1 SSD, and 3 HDD.

Plan to upgrade to latest processors.
With this change, I need to buy a new motherboard, RAM (DDR4 3200 MHz), processor.

Budget with RM3500.

Please recommend me best combination. Oh ya, can I just use back the rest of the component (sound card, NVidia GTX460)

Thanks in advance.

CORE I7 7700 (4C/8T) 1151 3.6 4.2 8M RM1399
CORE I7 7700K (4C/8T) 1151 4.2 4.5 8M RM1574
CORE I7 6800K ( 6C/12T) 2011V3 3.4 3.6 15M RM1993

Any significant improvement over the larger cache memory of processor.

I prefer Asus but there are so many type Maximus, Strix, Prime.
Which one to choose ?