You can buy high end graphics cards from Forsa, because most high end cards are made to strict quality standards from NVIDIA and have complex designs that cannot be easily modified. As a result, the worst you can get is NVIDIA's reference design which is not bad to begin with.
For mid-range and low end, be careful: Forsa hasn't been known to be a top quality brand. They skimp on capacitors, VRM circuitry and sometimes change the specifications (clock speeds) on the models without notice. If you want a cheaper graphics card, I recommend you go for Palit or Sparkle.
When looking at an NVIDIA graphics card, you might want to look at this channel partners page:
NVIDIA Authorized Board Partners
The brands listed here are Tier 1 brands, they have the closest relationship with NVIDIA and are able to get boards out faster as well as (to an extent) preference when selecting chips for making OC edition products.
Note that the following partners are NVIDIA Authorized Board Partners for Europe and Asia, but not for North America (thus they are not mentioned in the above page):
Palit
Sparkle
Leadtek
Gainward (same company as Palit)
Inno3D
Point Of View
These are Tier 2 brands. They are still good value for money but they will probably have delays getting an OC version card out, or in launching a new card on release day (though Palit seems to be on the ball pretty well, some of their cards have less than stellar OCing performance).
Any brand not in Tier 1 or Tier 2 are not unauthorized or illegal, but they are basically 3rd party designed and sold products, and thus the long-term support for such cards will be minimal at best. However, sometimes you'll still find a decent deal amongst these Tier 3 brands (e.g. ECS, Biostar graphics cards). You will rarely see overclocked versions, or fancy coolers on these brands.
d6bmg said:
Local prices are much lesser than the price quoted in flipkart.
Here in Mumbai I wouldn't say MUCH lesser but yes, lesser.
Also of note: Most (if not all) Tier 1 brands use very high quality capacitors, usually Japanese in their graphics cards, as well as using a better PCB design (i.e. more VRM phases, etc.) when using a non-reference PCB. Tier 2 brands may or may not use Japanese capacitors, however the capacitors are still in the "not bad" range. Non-reference PCBs may cut back on certain features like voltage control, SLI connectors or (rarely) VRM phases. These cards also sometimes skimp on the cooling, though in general they prefer to stick to something close to NVIDIA's reference cooler and PCB.
I have never used a Tier 3 brand in my life, so I'd not know anything about their quality. The information here is not definitive and based on my experience of using NVIDIA cards of different brands over the years.