Você diz:
I'm not a gamer, I'm an IA and web designer so the system is mostly for Photoshop and Illustrator work and the occasional knock around in command and conquer.
Neste contexto:
1) Is it worth adding the SLI connector, will it really boost overall performance (I'm guessing that the OCX card will then perform as the OC card does)?
Não aumenta significativamente o desempenho. E sim, o OCX trava / rebaixa para os limites de OC.
2) Are SLI connectors (the one's that run across the top of the cards) motherboard or manufacturer specific?
Eu acredito que a ponte SLI não é centrada na placa-mãe / fornecedor.
3) If I do SLI the cards will I still be able to use all four monitor connectors