Pusan weirdness

[hedley]

I'm a big fan of ToW & have all of the products.
Just bought Korea & had the first real problem I have ever had with the series.

I think it may be mission specific but I am not sure (without playing the whole game through...)
This where the game grinds to a halt. Enemy troops in unresponsive parade ground order. Armour from this combat group has already attacked & been killed.


The mission is Pusan I am the US defending. 2 attacks come in - the first doesn't impact the PCs performance but as the 2nd attack comes from a different direction I got sporadic slow-downs. The slowdowns aren't relative to the amount of action/units on screen.
These were about 3 minutes long every 5 mins until the 2nd armor group was destroyed.
The engine continues running whilst the stalls occur - the events stutter & freeze & then jump to the positions they would have reached but without interim animations or sounds. Mouse cursor active, but not game.

The 2nd attack groups' infantry never moves from the spawn point. As I approach them they do not return fire or react much & the closer I get to them / killing them the more the game stalls. It will initially stall for 6 mins for every 2-3 of action, this gets worse the further I go towards this group, showing up to 5 seconds of game activity & playing back only 5 seconds of audio between freezes. Again taking minutes to 'recover' for the next stutter.
I can get to the menu & it responds perfectly - saves & settings etc all respond.
Tabbing out during a freeze can cause the whole PC to freeze for minutes. Korea.bin is taking the most CPU - but only <20% - not enough to make a difference to the system in normal circumstances. Temps do go up in line with high activity tho - CPU rising from 28 - 52C in this state
I have tried altering :-

CPU affinity for the exe
EAX
Compatibility
Nvidia game profile
'Run as Administrator'

- no change.

Playing the Pusan mission from Korean side ran through fine, no stutters or any odd behaviour - (but different map).
I did see 1 CTD on the very first try to run this mission for Korea tho (on Start Battle) but it has loaded perfectly previously (for the US) & since (the US & Koreans).

Save game (just before the stutters kill it for me.) 3.54mb .7z Maybe someone can spot whats happened (AI script buggy? Devs?)