I've been researching this issue for quite some time in a vain attempt to make DD-WRT work for me on a WZR-HP-300GN. First, I purchased the WZR to replace a WHR-HP-G54 also running DD-WRT to make a move to 802.11n, and gigabit ethernet. I want network coverage at a neighbors houseso having a high power router with good range and edge network performance was important to me.
The WHR-HP-G54 had been serving me faithful for years running DD-WRT, with excellent performance and range, with often time 19-22mb/s at the neigboor location. When I switched to the WZR-HP and DD-WRT the performance at the same locations that had excellent peformance using the WHR + DD-WRT, were totaly unusable with terrible network peformance under a megabit tranfer rates if any transfers at all could occur, and poor signal/noise ratios, with DD-WRT indicating 18-19db/m if I played with it in signle channel mode.
After spending days reading about the issues with DD-WRT and the madfi driver, doing my own performance surveys and comparing the old WHR to the new WZR it is clear that the DD-WRT wifi drivers are not working well on the WZR.
I have both the WHR-HP-G54, and the WZR-HP-G300NH both loaded with the DD-WRT. The HP-G54 is using DD-WRT 15962, and I've used the DD-WRT 15962 and the what was it 14988 build that buffalo has. Using an ipad and viewing the s/n quaility and bandwidth test app... This is what I found.
The WHR-HP-G54 at the same physical test locations using an ipad had a consistentaly higher s/n, and bandwidth than the WZR-HP-G300N. When at my neighbors house using their desktop computer, with the HP-G54 as the router to connect to, their computer was able to get 11mb/s downlink speed and a s/n of 39. The WZR-HP using all builds of DD-WRT was at 20-25 s/n ration and only 500kb/s downlink speed. Both routers were in the same location, and each was only used one at time.
The bottom line at distance for me the WHR-HP-G54 clearly outperforms the WZR both using DD-WRT.
I switched the WZR to openWRT and range problems were solved. OpenWRT can set the TX power to 28, and now the router has better range than the WHR-HP-G54 and better performance.
There really is a problem with DD-WRT and the WZR-HP-G300HN. I can tell you the wifi on the WZR does not perform well. It seems to consistently offer lower performance and shorter range than OPENWRT using the same client devices, and not moving the router from its default location and only changing firmware.
I like DD-WRT been using it for years. But on the WZR DD-WRT is not a good match. The wifi driver obivously has performance issues and needs to be fixed. My recommendation is stick with the stock firmware, or move to OpenWRT. I don't like OpenWRT's user interface, and using it always feels like an intelligence test. But DD-WRT simply dosen't work for me, the range is too short, and the edge network performance is aweful.