A2000 - Rev 6.2 to 6.4 updates?

[Jope]

Watching a GadgetUK164 and he mention upgrading his 6.2 to 6.4 but I cannot find any info about this, anyone tell me what the changes are?

Basically the major differences are: Update the ROM to 2.04 or 2.05 and install a Super Denise.

Here's a list taken from Commodore's service bulletins. https://www.amigawiki.de/doku.php?id=de:service:upgrades:a2000_mainboard

You don't have to care about the 8375 related capacitor modification/Agnus swap. Just keep the 8372A, it is functionally identical. The 8375 chip mentioned in the modification list is a 1MB part just like the 8372A is.

And while we are talking A2000, I wonder if better chip mem can be used? the bottleneck is most likely the CPU anyway but a thought.

Unfortunately changing the RAM chips will not help. The original Amiga design is such that you can't go faster. The A3000 alleviates this somewhat by allowing 32bit wide accesses to Chip RAM, even though it is still an ECS machine. The AGA machines all have 32 bit Chip RAM access.

[Jope]

If you're using the Ramesses II, then you do not need to do any modifications to the motherboard. Installing the Agnus adapter and the Gary board is enough.

You'll notice the Ramesses manual has info about the Vbb jumper, which you must set to match your Agnus. The rev 6.4 capacitor modification was for the same reason - they shipped with a Vbb Agnus, so the capacitor was needed. The Ramesses II does it for you, so all is good.