For the 'Kin' achievements i had a hard time until i ended up using silly tactics for each of the 3 races to allow my team the win with a lot more ease, and a lot less frustration at my idiotic teammates.
Protos
Cannon Rush. You can see my description of it here.
The basic gist is: send a starting probe to their base (on Megatron) and set up a pylon and forge, then start planting cannons until they are all hampered enough that your team rolls over them.
Zerg
Spine Crawler Rush.
This works best on maps where all the bases are seperated.
This means your opponents all need to be zerg.
Harvest for < 1min with all of your drones. Build 1 or 2 new drones. Then save up for a pool. After the min has past send 2-4 of your drones into the opponents base. Then split them up 2 per opponent base. As soon as you have the resources turn those drones into spine crawlers behind their resource line. Use the minerals to funnel the drones so only one can attack your spine at a time.
If all goes well you will land 2 crawlers behind 2 different bases and it will cause enough economic damage that the other 3 players on your team will be able to roll over the opposing AI. If all does not go well, they will have attacked your crawlers and killed them. Save yourself the time and pack up and surrender. Just try it again.
Terran
I chose Protoss for my opponents on this one.
This works best on maps where there are two players per base.
I built fast into 3 barracks with tech labs and mass produced Reapers.
I then proceed to reaper harass the opponents, watching for striders and zealots to come defend while cleaning house of probes. If you are able to take out a nexus early, that's always very helpful.
If all goes well you did enough damage that your buddies can clean house, otherwise start over.
Hope this helps out, this is exactly how I did them.
Best Answer
It depends on the game and the OS. Many games are not written with multi-core support in mind, but still make use of OS-level primitives that cause the OS to migrate processes between cores, which in some cases can impact performance due to cache line misses and resource allocation issues, and depending on the graphics hardware this can theoretically make a big difference, although the difference will be greater on systems with multiple distinct CPU chips rather than multi-core CPUs that share a cache and so on. Some games might even break without CPU affinity set, because they were only tested on single-core systems and make some bad assumptions about the order of operations that occur in asynchronous APIs.
The best thing to do is to try it and measure the difference, if any, and re-measure it every time there's a new graphics driver or API version update, since future versions of graphics drivers in particular can change things immensely.
That said, if a game is written to take advantage of multiple cores, then it never makes sense to set the CPU affinity on it.