Can some one tell me what exactly nitrus can do for sins? besides rotating turrets? - i dont understand all the multi core stuff.. will nitrus help with the limit? will they be able to add more ships?
There are two things holding back ship count in Sins I: endgame slowdown and the 2 gig limit. Nitrous fixes both of these.
Think of it this way... Your CPU in your computer probably has several threads that it can run simultaneously which means that it can do several things at once. The naive way to program a game results in a single thread that is executed by the processor. In such a case, the only thing that matters in terms of how much can be happening at any given point is the clock rate of your CPU. My brand new (and I do mean brand new, I built it yesterday and and installed Windows today) CPU's clock rate is 4.0 GHz which means that it can do twice as much stuff in a program (like a game) in a given amount of time as my laptop which has a clock rate of 2.0 GHz. Sins of a Solar Empire is a single-threaded program meaning that my new PC will be able to process twice as much stuff (give or take; yes, I'm simplifying it here) in a given time frame as my laptop without having slow down the game to keep up. In other words, it takes twice as much stuff going on for it to hit endgame slowdown.
Multi-threading largely fixes this. Due to technical limitations, clock speed can't go much higher so instead, engineers decided to add more "mini-processors" that will run in parallel. Thus, my quad-core i7 can run 4 threads at once instead of just one (again, I'm simplifying because of hyperthreading)! Unfortunately, these other three cores go unused unless the software tells them what to do. Because Sins I was written in the naive way, those other three cores are just sitting there twiddling their thumbs while the one primary core is working its butt off trying to crank out thousands of ships and paths and is generally being tortured.
Nitrous, unlike the Iron Engine, is a multi-threaded engine so it can take advantage of the additional cores in a processor, thus allowing for dramatically increased calculations per second. As such, the Nitrous Engine is capable of things like calculating the rotational headings not just of a thousand ships like in Sins I, but also the rotations for the 4-5 turrets on each one of those ships!
Summary: the Iron Engine can't process more than one thing at a time so most of your CPU's power is wasted. The Nitrous Engine, however, can take advantage of this leftover power and can use it to perform significantly more calculations per second.
2 Gig Limit
Without getting too technical, the number of memory locations a computer can access is about 2^X where X is some number of bits. 32 bit systems then have much less maximum memory than 64 bit systems which for all intents and purposes in this day and age is infinite. Thus, the maximum number of bytes a computer can access is 2 billion bytes = 2 gigabytes.
Now, your system is probably 64 bit. 64 bit systems are just simply better because they allow for a system to have effectively infinite memory whereas 32 bit systems run into memory problems when running modern games. Unfortunately, it's not enough for your computer to be a 64 bit system to fix the problem with Sins I. You need your software to also be written for 64 bit systems or it'll just run as an inferior 32 bit program (64 bit systems are backwards compatible with 32 bit programs) unless you do some very unpleasant memory gymnastics which I won't detail here.
The Iron Engine is a 32 bit program written at a time when 32 bit systems were still common. 32 bit systems are now going the way of the dinosaurs as 64 bit takes over. Nitrous is a 64 bit program.
Summary: at the time of Sins I's release, 32 bit systems were beginning to be replaced by the superior 64 bit systems which are immune to the 2 gig limit. Because 64 bit systems were backwards compatible but 32 bit systems weren't forwards-compatible, the devs decided to make the Iron Engine 32 bit so that it could have as many customers as possible during this volatile transition period between computer architectures, even if this meant that Sins I would always be afflicted by the 2 gig limit. 64 bit systems now reign supreme which is why the new engine Nitrous is a 64 bit program.
So what does all this mean?
More ships, prettier textures, prettier particles, better pathing, a combat/buff engine that is more responsive, better fleet maneuvers, etc. Basically, anything in the game that involves math or memory would be much better off with Nitrous.