As this issue seems to have been resolved with new drivers I'll mark this thread as solved now.
I've been having this issue as well, and it has gotten worse since China Rising. Previously, I could play 6-8 games before the leak started happening, but now it's a 50% chance that at the second map load the NPP starts rising and I have to alt+f4 the client as a rescue measure. I now play with task manager running on my second monitor. I switched from my old Radeon 5870 to my brother-in-laws unused 6870, which seemed to make the problem worse.
Specs:
Windows 8.1 64-bit
Radeon 6850 1GB
ASUSX58T-P
6GB RAM
Dual Monitors, playing in Borderless Window, mostly medium with some high
Some notes:
1. I'm running the most recent, non-beta ATI driver.
2. Mostly play Conquest Large with 64 players. I'm uncertain if this impacts it, but it seems I have the issue less frequently on Rush.
3. Changing video settings did not remove the problem.
4. None of the suggestions have worked for me.
