Well first off -92dB is a horrible signal. The noise floor measures out of band interference meaning everything outside of the current band you are using (ie: 2.4Ghz). It doesn't take in account for other AP's in the area running in the same band. At least that's what I've got from previous threads on this forum, and I believe a MT rep confirmed this.
REF: http://forum.mikrotik.com/viewtopic.php ... oise+floor
In an ideal environment atheros cards claim to operate at these lower Rx sensitivities, and I've seen them perform well at lower signal levels in rural areas with realitively low RF interference. However it all depends on the environment, and 2.4GHz is really crowded. We strive for -75dB or better for our 2.4GHz wireless installations. Anything worse than that leaves you with little fade margin and the possibility of poor performance down the road. We've noticed the 5.8GHz band works much better and with the Ubiquiti SR5's we can achieve high throughput with very poor signals (high 80's to low 90's).
Here's some questions for you that will help you get the answers you need...
What's the total EIRP of your AP in dB (include the radio and antenna gain)?
What are you using for client devices (laptop cards, Fixed CPE device, etc..) and what is their respective EIRP's?
What band are you operating in? I saw you mention 802.11g, I hope you're not trying to use this in an outdoor environment over long distances...
What type of application is this? (hotspot, fixed point to multipoint wireless, point to point, etc..)
Post your entire config omitting unnecessary data (such as public IP addresses), to do this open a terminal to the MT AP and type "export file=filename". To retrieve this file you have to FTP to the MT box, open it in a text editor and paste in the forum.
Also it's good to post hardware information and RouterOS version as I see you've done in a previous post.
The problem you're describing sounds more like a physical or data link layer issue. The poor ping times could be attributed to the poor signal quality. Have you tried connecting at a closer proximity with a better signal, and do you still experience the same latency issues?
The more information you provide and in a more organized manor will help people HELP you.
Also I'd stick with the CM9's, Ubiquiti SR5/2, R52's, and other proven cards. Prism based chipsets work, but lack some features like WDS. I tend to stay away from any of the SENAO products, as I haven't had a chance to test them, and wasn't impressed with gear I've used in the past from that company.
I've also run into issues with atheros based chipsets mainly the SR2's and older Prism cards not performing well together, such as high latency and random disconnects. Using newer CPE devices seem to work better.