I don't know how to explain this in detail, but I think you need to google up about bandwidth speed and bandwidth capacity.

Having a bigger capacity doesn't mean your connection can be fast.
But a faster bandwidth can be faster even if you are just using a 1mb line.

AFAIK, Maxis' routing is still through TM since they are the main in MY.
I guess there will be no different, I would stick to your RM88 unifi if I were u.

Just some example (Downloading a movie from US):
10mbps - means average download speed can be reach 10mb, but if the routing and line to that US server that you're downloading is slow.. Then u might just capped at 512kbps.

1mbps - your average download speed can be as high as 1mb, and if the connection and routing is good, you will be getting a stable and firm 1mb all the time.

So far from my gaming experience, the data packets being sent by host server are usually very small. (maybe less than 200kbps)
But it is the routing/connecting that could not handle even for this small little packets. Thanks to TM =)