Chess uses 98% CPU

Actually the Chess program in Mac OS (at 50% or higher difficult) uses very complex and powerful algorithms to calculate all possible moves and it is very CPU intensive... at 100% difficulty it takes minutes for the computer to make a move (even on CoreDuo) so its definately not a bug.

To save battery I would suggest using 50% or lower difficulty or play with a friend 🙂

MacBook Pro 1.83Ghz 1GB RAM Mac OS X (10.4.8)

This is just one of those programs that uses A LOT of cpu processing. Chess has been known to run on super computers even today, the more powerful chess is the more cpu it takes and the one in Mac is very powerful.

You are lucky it does not take hours at max settings (takes around 5mins)

"At the maximum setting, it may think for hours before making a decision."
http://en.wikibooks.org/wiki/MacOS_X_Tiger/Meet_theApplications/Chess

Heavy CPU usage (and sometimes using a good deal of RAM to set up the predictive options) is perfectly normal, and an indication that your MBP can handle the resource demands of a very demanding application, especially if your game is computer versus computer.

No bug here. The game of chess requires "looking to the future" to evaluate the outcome of possible moves. That's heavy-duty computing. The level of chess your MBP can achieve was beyond the capacity of computers not that many years ago. Of course, a supercomputer should be able to beat your MBP fairly often, but probably not every game. 🙂

Acquiesce,

Whether or not there actually is a problem with Chess isn't the focus of this reply.

Instead, I am addressing your original question concerning the CPU usage. CPU usage for any user apps is indicated in relation to the total of that user's current CPU allocation. In the case of your Chess example, 98% means 98% of your CPU allocation, not the total of actual CPU capacity.

As needed, and as possible, a given user's allocation will change dynamically, but OS X tends to keep a healthy reserve held back for additional processes.

To really see what is occurring, perform your test with Chess again, but this time make sure that the CPU "pane" is showing at the bottom of the Activity Viewer window, and pay attention to the percentage of total CPU allocated to you. Chess's usage (98%?) is a percentage of the percentage given to you. As you will see, your allocation will change over time, but it should not approach 100%. So, Chess is using 98% only of what you are currently given.

Now, while this test is running, open another application. What you should notice is that your CPU allocation will jump, at least temporarily. Also, you should not experience any real "lag" in the response of the new app just because Chess is thinking hard. It is for exactly this reason (among others) that OS X holds that "reserve" CPU potential at almost all times, and this is one of the things that makes OS X such a multi-tasking powerhouse.

Scott

Yeah, well, I'm not convinced.

What is the point of this thread honestly? We told you Chess is a cpu intensive program get over it. There is a lot of other people with REAL issues on this board that would rather seek attention than to convince you how or why Chess requires lots of cpu.

I don't want to be mean but you are dragging this thread way longer than needed.

but 98% is actually just under 50% right, because it has two processors?

When I had to do the battery exchange for my old iBook G4 the instructions Apple sent told me to run Chess to discharge the battery. I thought that to be pretty odd.

Does it vary based on difficulty or level setting?