X-Fi EAX with toslink /optical?

Hi, I'm new so hello everyone!

I've been looking around and I'm not sure so can you please answer this: I want to buy a X-Fi card however I'm not sure if, gaming wise, using the optical output with my Z5500 would be all I need for using all EAX modes, or is the optical output only for movies / music, and I still need to use analogic for EAX / gaming?

Also, it's so obvious the improvement of the optical output over analogic in gaming with X-Fi?. It is with Dolby Digital but does EAX really uses it properly?

I do ask this since I'm wondering which X-Fi type for for, FPS or Xtreme music, and though I like FPS it seems to me tougher to install, together with price reasons of course, and maybe it not being worth it for gaming only.

Thanks a lot in advance.

First, thanks for answering.

Great to know about analogic, I thought optical was best so glad to know that

I was wondering, does the X-Fi decode properly Dolby Digital for games like Splinter Cell: Chaos Theory? I know it can do movies, but DD games? And, in case that there comes a game with both DD and the latest EAX, which mode would be superior?

So if analogic is better than digital, why should I go for the FPS besides the extra RAM. The external bay with all the in/outs looks interesting but won't proplerly improve gaming sound either, so performance/quality wise in gaming, besides the RAM, is there anything else?

That's all my doubts I swear, thanks a lot

dont have splinter cell so not sure what settings you have there. My X-Fi can decode any dolby you throw on it anyway. In games usually only non-interactive parts are in dolby.

Well, if you have a receiver or simply 5.1. setup with digital input you may choose Dolby Prologic so that rear channels signal is matrixed into front channel signal and sent to your external DAC for decoding from Dolby PL and converting into analog. Maybe you mean Dolby ProLogic...
But in this case you bypass the whole EAX processing.

Giving up on EAX just to avail digital streaming is not something I would do, defenitely not with games. Unless you are stuck with speaker set that does not accept multichannel analog inputs - select eax and analog.
From my exprience analog cables, if properly shielded, are enough for gaming or HT PC.