Hi,
What is your rig specs?
Chassis? perhaps you need more chassi fans?
PSU?
Etc?
It is important that the airflow which is the key to cool down the electronics, goes in the right direction and have the ability to get rid of the heat out of the chassis.
The same principle is still valid if you consider water cooling, because there are still some heat from the motherboard itself that req. airflow and a heavy graphics card will induce more heat into the chassis.
If you are going to overclock, then not just the CPU will get hotter, as well the surrounding components of that area and the memory's.
It could be interesting what temperatures you have today:
Download and install HWmonitor (Free) install and pay attention so that you unckeck any third party s/w during installation or just take the zip-file which do not contain any of these
http://www.cpuid.com/softwares/hwmonitor.html
Then start HWmonitor (it will check all temperatures and voltages) and have it it running in the background or on a second monitor, then start the game.
After 15 minutes of game playing, quit the game and take a reading.
There are three columns:
Value: shows the actual readings
Min and max speaks for it self
You can also in the menu File > Save monitoring data => and post it here so that we can have a look at it.
Use CPU-Z (free) make sure to uncheck any third party s/w during installation, well same thing
http://www.cpuid.com/softwares/cpu-z.html
In the memory Tab it will tell you what memory clocking are at:
For example if it says DRAM Frequency 1066MHz then you double it by 2 (1066x2) the memory are running at 2132 MHz
If it says 800Mhz - the memory are running at 1600MHz.
The easiest way to overclock, is to start with Enabling Your memories inbuilt
Intel XMP-profile in the BIOS OC or advanced menu settings - if your memory have support for this. It will not only enable the memory's high settings (lower timings, higher frequencies, sometimes higher voltage and everything), it will also overclock the CPU somewhat.
Then you should run HWmonitor again preferable with a stress program to make sure that everything is stabile and the temp and voltages are within their limits.
Again run CPU-Z and check your new values in their respective tabs.
Here is a site that list the best CPU coolers:
http://www.tomshardware.com/reviews/best-cpu-coolers,4181.html
Best regards from Sweden