There is content regarding wireless:
Whereas throughput on Ethernet-connection could depend on limited CPU power alone, the throughput on a 802.11-connection depends on many more parameters.
|When you measure the throughput of an action (the copy of a file), what exactly are you measuring? The throughput of the payload, or the throughput of payload + overhead? For Ethernet the difference can be small, but for DSL-PPPoE or 802.11 the difference is bigger. So it's always good to know, what actually you are measuring. A good manual will tell you what a software is precisely doing.|
Whether an OEM firmware gives you better throughput then OpenWrt is a matter of SOFTWARE (since both run on the same hardware…). So ask yourself, what Operating System is used for the OEM firmware. Probably some sort of GNU/Linux. In Linux, drivers are part of Kernel. In OpenWrt we use quite new Kernel with even newer wireless drivers. So it IS possible, that OEM firmware gives you better throughput, but since both, OEM and OpenWrt, use Linux kernel and Linux drivers, well, …
Yes, but cranking the power to the maximum won't help you any. You might transmit farther but the noise level will be higher (and will probably bleed into the neighbouring channels; that looks like this then) and your recieve sensitivity won't be improved any, limiting your distance. If you want better range go buy better antennae.
"With regard to ath9k development, last year is ancient. Additionally OpenWrt contains a number of ath9k patches which are not yet mainlined, so its usually a bit ahead."
→CRDA (Central Regulatory Domain Agent) takes care of everything!
To not cause havoc in your neighborhood, and also to not break the law and pay a fine!, your IEEE 802.11 setup needs to obey the regulations for your current location. But you do NOT need to bother with all of this, because the CRDA takes care of this for you.
Any country has some kind of regulatory authority in charge of regulating the radio frequency spectrum as these differ from country to country. In case you want to inform/convince yourself of the current regulations, there probably is an official web page on the Internet with this information. For Germany, this is the ⇒"Bundesnetzagentur". AllgemeinZuteilungen is current valid law as pdf, concerning frequencies and the allowed maximum transmit power.