[CRASH][Crash dump inside] Crash during gameplay, around 10 minute mark, CPU is at 100%

The client crashes when in game. Approximately once every 3 matches. When it happens the CPU usage is always at 100%. This happens around the 10 minute mark. Never right away in the beginning of the game and never in the late game.

Normally my CPU usage is at 50% with only League of Legends running. There are regular short spikes of CPU usage to a 100% - they happen at the same time intervals, every few seconds, you can see this on the screenshot here. Then once in a match, it will go to full 100% for around 30-60 seconds, the game might lag slightly. During this the game might crash, or it might not. It doesn't always crash, but when it does - it is during this 100% CPU usage. For the CPU usage I double checked that this is specifically the game, not any other process.

During the 100% CPU usage my mouse will lag (I assume the client takes up all the CPU time and the input is processed not as often). To fix this I set the League of Legends' process priority to Below Normal. Before I did that the game never crashed. So this definitely is a cause in some way. However if I don't do this, the mouse lags and makes the game unplayable at times. So I would really love it, if you guys could fix the crash.

My PC: Core 2 Duo E6300 2.80 GHz, 4 GB RAM, AMD Radeon HD6670. Windows 7 x64. It is an older one, but it fits under the League's requirements. Please don't dismiss this as "your computer is too slow". The game can be played fine almost all the time. I play on low graphics with the "Close client during game" option enabled.

Please find 3 crash dumps by following the link. I'd be happy to provide any additional info. I can also record and provide ETW (xperf) traces for the CPU usage if needed.

Thank you for reading. If this is not the place to post this - please direct me.

UPDATE: Uploaded another crash. Dump Screenshot Game where it happened