Arena 3 and Houdini 1.5

I downloaded these two softwares yesterday because i heard that houdini was a very strong chess engine (and free) and Arena 3 because i needed it to use Houdini. However, after dowloading, I realized that there were two Houdinis: Houdini_15a_x64 and Houdini_15a_w32. Which brings me to my first question:

Are they the same, different, or two parts of the same engine?

Currently I have 1 loaded as engine 1 and the other loaded as engine 2, and, while it works, I want to make sure I have the best possible set up.

Next up, it displays depth of the search as some type of fraction, '25/52' for example. As someone who is used to thinking of depth in moves or half-moves, what does this fraction mean?

Thanks for the time and help

I'm not sure about the second q, but the 1st q I know!

OK, it means the 32 one is for standard pcs, desktops/laptops

The 64 one is for multi-core processors, basically a computer with two seperate processors to do the tasks, making it  30% fastter then normal, at least according to the website.

I'm not sure what computer you have, but if you have a standard pc, i dont think it will let you load the 64 one, at least thats what happened to me.

Just so you know, I know Houdini is strong but I dont like its positional style, it plays moves that are safe, but Rybka is more "aggresive", it is best to use 2-3 engines for a more rounded view of analysis.

you already have houdini, so you can get rybka 2 for free, or buy version 4

The last one, maybe stockfish, although it isn't that strong. 

Maybe Fritz, Junior, HIARCS, etc. if you want to spend a little money.

Thanks for the help

If anyone can explain the search depth question that would be great :D

I believe Metaknight is correct.  I have Fritz 13 and it shows that as 'depth'.

1st question - They are two different engines. The Houdini_15a_w32 engine is one compiled for 32-bit operating systems, while the Houdini_15a_x64 engine is compiled for 64-bit operating systems. Both will run on a 64-bit OS, but only the Houdini_15a_w32 engine will run on a 32-bit OS. On a 64-bit OS, you'll usually get a little better performance from the x64 engine.

2nd question - There are actually 2 windows with similar looking output. The window displaying something like "Depth 17/39" is telling you that the engine is searching to a depth of 17 plies (half-moves), with some search extensions reaching as far as 39 plies. There's a window just to the right that displays something like "c7-c5 (3/35)". This window is the one that tells you the engine is currently evaluating move c7-c5, which is the third move in a list of 35 legal moves.

Hope that helps!

Yes, that helps out alot!

Thank You

If I'm not mistaken, if your PC is running Windows 7, then your PC is a 64 bit machine.

Well, Microsoft does make 32-bit versions of Windows 7 for PCs that have 32-bit CPUs.