Chessmaster 10

My cousin gave me his copy of chessmaster 10 a few months ago. However, I still don't really understand how the personalities work. Do they actually play at the ratings next to the name? Because I find that hard to believe. Are blunders incorparated into the programming?

Each player has a randomness level given to them, by the 1700's this has all but dissapeared. The higher the randomness, the more often they play random moves. And believe it or not I think this is a moderately accurate model of human play as a lot of human players (Of all ratings) occasionally play moves which cause them to say, "What was I thinking. I can't believe I played that."

Also, the rating are a combination of approximation, playing rated games against the computers and probably a little bit of pre-release play organized by developers.

Osmano> Do they actually play at the ratings next to the name? Because I find that hard to believe.

The initial ratings of over a dozen personalities were calibrated via games against USCF-rated players (since CM9). The ratings of other personalities were then derived based on their win/loss against these computer opponents, and finally, there was some guesswork as to the effects of increased CPU/memory. The ratings (since CM9) are generally regarded as accurate +/- 50 points if you play a variety of opponents in tournament mode--eg, equal time controls, both colours, no takebacks, and not focusing too much on that one personality above your rating you can beat.

Osmano> Are blunders incorparated into the programming?

Yes. Upto the 1199 level personalities have a low search-depth: they don't see too deeply and will fall for a gazillion tactics. At the 1201 to 1699 level the personalities tend to make better moves than human opponents do but then they make random blunders. It averages out rating-wise, but many don't like this. Humans make blunders but usually they don't throw material at you--you often have to spot a tactic or put them in a difficult situation where the pressure makes them crack.

Thank you for these good answers . It clears up quite a bit. 

At the 1201 to 1699 level the personalities tend to make better moves than human opponents do but then they make random blunders.

Is this the limit? Most of the opponents I play are at ~2100 level and some mistakes seem quite elementary.

Not that I'm knocking CMX of course, it's a great program and engine. 

Osmano> Is this the limit? Most of the opponents I play are at ~2100 level and some mistakes seem quite elementary.

Hmm... that's odd. A ~2100 level opponent should not feel weak to you given equal time controls and no takebacks. I recall seeing some posts in the forums about CMX and CMXI playing badly on some computers at fast time controls (<=5min/side).

Some examples, I won't post the whole games but against personality "Laura" (2096 apparently) I was up a bishop, a rook and 2 pawns by about 20 moves. Some moves the personality would trade a bishop for a pawn even when there was no threat. These type of rash moves occur with other personalities too.  The time was 10/5 fischer. Is it a bug?

Deadpoetic - agree about the openings! Very in depth, though it is quite useful.

Osmano> Is it a bug?

If you're up by that much, it's probably a bug. Alas, they are no longer fixing new issues in CMX, so all I can suggest is to download the latest patches.