I need some tough positions

[Donbaek]

Hi all.
I'm new to open-chess, and to chess-programming (but not to programming or chess).

I want to experiment with some more alternative/selective searching algorithms, and for that I need some very tough (but not impossible to solve) positions.

The ideal kind of position would be a position where....
1) Most (but not necessarily all) of the top-5 engines can't solve it within 3min running on two i7-cores.
2) Most (but not necessarily all) of the top-5 engines can solve it within 1hour running on eight i7-cores.

I need quality over quantity, just 4 positions like this and I will already be of to a good start.
It doesn't matter much weather it is closed or open positions, tactical, sacrifice or long term strategical moves, endgame or middlegame as long as their are tough but not impossible to solve.

Anyone have such positions, or can point me in the direction of a tough test suit of positions?

Thanks
Donbaek

[User923005]

Some of these are pretty hard (look at the links in the lower part of the page):
http://glareanverlag.wordpress.com/2012 ... n-magazin/

Run them through your engines and see what you find.

[Donbaek]

Thank you User923005
These are exactly the kind of positions I was looking for,
several of them are plenty tough enough for my purpose
Thanks