6000RPM is the highest, and if the Mac is beginning to overheat, it will shut down itself. So there is no need to worry.
To control you fan speed manually, you could use SMC Fan Control, but know, that the minimum fan speed is still 2000RPM, which you can't lower that way, and which you shouldn't. But you really don't need to manage your fans with an external tool, unless you don't want a hot machine. But gaming is CPU and GPU intensive, thus there is no way around higher fan speeds.
And then there is this too:
Adobe Flash Player is CPU intensive, thus more power is needed to feed the CPU, which results in higher temperatures and often higher fan speed(s) on mobile computers. As more power is used due to Flash, the battery life of mobile computers is shortened by a good bit.
To check, if Adobe Flash Player is responsible for less battery time, go to
Applications / Utilities / Activity Monitor and select to show
ALL PROCESSES and sort by
CPU.
There are a variety of Flash blockers for all the four major browsers available.
A Flash blocker does what it says, it blocks Flash content, but via a click on the marked Flash object, the Flash object can be activated and used.
- Safari: ClickToFlash, for which there is an extension and a plug-in; CTF allows you to download YouTube and other kinds of MPEG-4 encoded video too.
- Opera: has a built-in Flash blocker
- Firefox: Flashblock is an add-on to block Flash
- Chrome: FlashBlock is an extension to block Flash
Also make sure to have the latest Adobe Flash Player version running, you can get it
here.