1080p movie:
AS 2.5.8 = +1100MB overall RAM used.
AS 2.6.4 and 2.6.5 = 1700MB each.
Now curious part...
4K H.263 4mn 2s Bit rate 51.0 Mbps 3840x2160 pixels Frame rate Constant 29.970 fps
This video + AS 2.6.5 = +1.55GB RAM.
I need an h264 now to test
Even more curious:
Codec ID: avc1 Codec ID/Info: Advanced Video Coding Duration: 3mn 46s
Bit rate: 22.5 Mbps Maximum bit rate: 58.1 Mbps
Width: 4 096 pixels Height: 2 304 pixels Frame rate: Constant 24.000 fps
This video + AS 2.6.5 = +1.985 MB RAM.
Sorry but to me it looks like there are personal reasons for not to use it.
As a USER I can say that crash when searching feels like Big bug. While having to patch smth with 4GB Patch feels like Developers successfully fight with natural limitations and support product and customers. Just my 2 cents;)