Thank you!
I've backed up my settings so tomorrow I'll see if I can push it any further but at least I know now this router can actually handle decent speeds with good latency.
Yes setting the rate/speed to zero disables shaping in that direction. Some people report acceptable bufferbloat on 1Gbps links even without traffic shaping, so will happily shape only on egress. But that really depends on how well your link operates and on your expectancies, your network your rules/policy
Last week I installed a vanilla Release v0.6.2 on my brandnew Belkin RT3200. I got a 1000/50 Vodafone Cable connection (Arris TG344DE as Router) and the Belkin is set up as a DumbAP.
Now that the dust has settled and it seems that the near optimal settings were found:
Could someone give a newbie like me (and maybe ohers) the necessary steps in detail to achieve such speeds on base of a plain v0.6.2?
0.6.2 is the latest UBI installer that modifies the u-boot bootloader and the partition structure. You need to run that once, when you originally install OpenWrt E8450/RT3200 UBI-variant specific bootloader and along it also teh special initramfs recovery instance.
After installing that, you need to use that initramfs instance to install/sysupgrade the normal run-time OpenWrt. That can initially be the sysupgrade image version published by @daniel along with 0.6.2 installer, but can also be any later OpenWrt release or snapshot.
Once you have installed the new bootloader, you can quite normally just sysupdgrade to the newer OpenWrt images, and you are not tied to the 0.6.2. (but the underlying bootloader used in the early bootphase remains the u-boot by 0.6.2)