First of all if you have a PC with anything other
than i810 motherboard, you have a SIS 6326 or a Trident
display card under your hood.These cards are just 2D cards,
they are supposed to have 3D support for Direct 3D but the
support is not proper so the 3D special effects are either 
not shown properly or are completly missing and the performance 
is so low that almost all 3D games are unplayable expect for 
a few oldies.
Now some info about the cards avaliable in the Indian market.

Intel i740,i810,i820,i815:
   i740 card supports almost all major features of direct 3D 
   and OpenGL.It is was one of the popular 3d cards but it's 
   not readyly avaliable anymore.It's perfomance is not good 
   enough to run newer games like unreal tournament in direct
   3D although it runs quake III at a playable framrate on a 
   good processor. The other problem with this card is that 
   updated drivers for this card are no more avaliable the 
   lastest driver avaliable is the pv4 which supports only 
   directX  6.0 where as current version of driversX  7.0a 
   and version 8.0 with a lot of new features is just around 
   the corner  so newer games cannot run on this card.The 
   intel series of integrates display cards i.e i810,i815,
   i820 are based on enchanced i740 core(i752).   
   Their performance is in the same league as I740.These 
   cards are inbuilt in the motherboard and hence there is 
   no scope for upgradeation as these boards, with the 
   exception of i815 dont have a AGP slot the other problem 
   is insufficient memory ,most of the boards are shipped with
   only 4MB ram which is far too less by gaming standards.
   These cards are only for occassional gamers who run games 
   at low resolution and are not interested in detailed
   graphics,the only benifit is cost.

Nvidia Riva 128:
   It is one of the older are from the Nvidia stable and now 
   its avalibility is sparce .It supports most of the standard
   Direct 3D and openGL features .The good thing about this 
   card is that updated drivers for this card are still 
   avaliable .The performance of this card is similar to that 
   of intel i740 hence the card is only good for ocassional 
   gamers.

Voodoo 2:
   This card is from 3Dfx the first manufacturer of 3D cards 
   for the intel platform and till rescently was the most 
   preffered gaming card.It is a pure 3D card and it requires 
   a classic 2D card to work .It is even possible to attach 
   two Voodoo card in sli to get a superior performance .The 
   performance of this card is in the same league as the Riva 
   TNT or Voodoo Banshee.It supports Direct 3D and 3Dfx Glide 
   api.There is some amount of openGL support in form of miniGl
   (openGL MCD) with the help of which it is possible to run
   games like quake 2 & 3 but the per formance is not that good.
   The other problem with tis card is they dont support true 
   (32 bit) colour and no agp support.Voodoo range of card give 
   the best performance in games based on 3Dfx glide api.It is 
   avaliable in 4MB and 12MB form.

Voodoo Banshee:
			
   It is the second 2D/3D card from the house of 3Dfx afte their 
   first atempt Voodoo Rush failed to take off.the performance 
   of this card is similar to Voodoo 2 and Riva TNT.It has the 
   same problems as the Voodoo 2 and is on the way out as it is 
   replaced by Voodoo 3 .It is avaliable with 16MB SDRAM  
   
Voodoo 3:     
		    
   It is based on he all new VSA-100 core which is also used in 
   future proucuts of 3Dfx voodoo 4 (it has two of these )and 
   Voodoo 5 (it has 4 of these).The performance of this card 
   is in the same league as Riva TNT2.It has the same problems 
   as other Voodoo cards.It is avaliable with 16MB.