Today I got Soul Calibur 4. I had heard that the install was optional. I loaded up the game and and noticed the optional install in the options menu. ( First i had played a few games without the install because i wanted to see the load time difference) So im at about 10 % and i accidently press Circle and it cancels the install. Thinking that i had accidently corrupted my data i exited to the XMB to check everything was ok. Low and behold i went into Game data utility and noticed 200MB of Soul Calibur 4 Data ( i know there was a patch that was 16MB ). So i load the game back up and go back into the optional install menu and press install. ( this time around i notice it goes up to 10% really quick). So it turns out you can install as much or as little of the install as you want. Handy. My question is what difference does partially installing the game do compare to Fully installing the game with regards load times, textures etc, if any difference at all?

I would imagine it would affect different bits of the game... so if it has only installed some then some menus will be faster and some will be the same as without any install.

(I have no idea I don't have a PS3, but this makes sense to me)

What I find strange about it is that the game now has to wonder whether the bit of information is on the HDD or not as opposed to knowing said bit is always on the disk and said other bit is on the HDD.

Yeah thats what I was thinking ^^^, but im not sure enough, I'll try testing out installing different amounts see if that affects it in any way

how strange i never really noticed, it would be good of someone did a comparison of the game running installed on hd and no install on hd

It seems like it just kept whatever installed data it had completed up until the point where you stopped it. If you restart the install it will probably continue where it left off. Not sure if the game is actually reading anything from your drive. If it does, that would be interesting, but it seems like a decent sized problem to be able to install any amount of a game that you want and still have it work.

I actually didn't notice a difference. That's probably because I generally don't care too much about loading times in games (except the PSX remake of Chrono Trigger... god forbid).

But whether or not it makes a big difference to me, what have I got to lose? I have a 60 gig and only... 2 games. I can keep that installed data for a pretty long time, so it's not a hassle. Plus, there's an "Uninstall" option, so it's all good.
And I wouldn't think that you have anything to lose either. I say just install.