Specifications wise Corsair TX850 is really good and being priced at Galaxy @ Rs.13k, (1k less from Silent Pro).
Silent Pro is 1k Expensive and you are paying that extra money just because its Modular. Its providing 66amps on 12v rail and the maximum output power is 792W.
Corsair TX850 having 70amps on 12v rail and providing 840W on 12v Rail. And its output power on other rails are more than its Labled Power, which means It can provid even more.
So the obvious choice should be TX850.
Aur haan ... Modular PSU ka itna koi faida nahin hota. Waisay he logon ne Fazool Main sar pay charha k raha hay. If you still want a Modular PSU, then Corsair HX850 is a Modular PSU but you wont find it in Pakistan. It might cost you a couple of bucks more like 15k, but it will be worth it IF you intend to purchase a Modular PSU.