I wish there was
Fix your fan or clean your computer or find out what the problem is and fix it.
Do not pretend there's anything you can do to not have your computer overheat by faffing around with the performance in the long run. Ignoring the issue will only lead to more expensive repairs or replacements.
I 1000% agree. I've had this issue and I know my way around computers.
TC, the reason your computer is crashing is to protect itself. What you're doing is ignoring the source of the problem. Stop playing games and get it fixed, otherwise that computer of yours will be more than slow -- it will be fried.
Does your frame rates slow down tremendously from the start of a DOTA 2 match to its ending? If so, that's your CPU's way of protecting itself. Eventually, it crashes to ensure it doesn't get any worse. If your computer freezes up completely (desktop and all) that could also be a video card issue.
Either way, what you described seems like an overheating issue. Re-apply
thermal paste to the top of your cpu (do this for CPU's over 5 years old imo), and re-seat the heatsink and fan. Ensure all your fans are operational. Ensure the fans on the video card also work. Make sure no wires are obstructing the fans and consider using a modular or semi-modular power supply (if you don't have one) to reduce the amount of cables to promote better air flow. Open up your case about every few months and use compressed air to remove dust -- focus on the fans and heatsinks, but get as much out as possible. I recommend testing the compressed air procedure first, just so you don't go wasting money on thermal paste and other ideas. Avoid setting your computer on carpeted flooring, or even the floor in general, and consider not smoking at your computer. Even if you're not concerned with cooling, these procedures can also extend the lifespan of your computer parts.