The question of which games you play should also be answered, because only some games benefit from SLI . . and the benefit is NOT linear (ie: you don't get anything close to twice the performance from two cards versus one), and in some games, the performance will be worse than with a single card.
What games are we talking about? Please don't mention etc here. Also list your current specs like so:
CPU:
Motherboard:
Ram:
SSD/HDD:
GPU:
PSU:
Chassis:
OS:
The question of which games you play should also be answered, because only some games benefit from SLI . . and the benefit is NOT linear (ie: you don't get anything close to twice the performance from two cards versus one), and in some games, the performance will be worse than with a single card.