As many of you know, my old laptop that I was using to test PCMCIA versions of the bcm43xx hardware died a few weeks ago. Thanks to the generosity of the contributors to the project, I was able to replace it with a modest computer purchased on EBay. It is an M-Tech eSlate 400k, which has an AMD 450 MHz CPU and arrived with a 4 GB hard drive with Windows 98. Using parts salvaged from my old computer, I was able to bring the memory up to 256 MB, the maximum supported by the motherboard, and it now has a 100 GB hard drive. I loaded openSUSE 10.2 on the machine and downloaded the wireless-2.6 git tree. The machine is slower than the CPU speed would indicate; however, it gets the job done.
I now have 3 different versions of the bcm43xx hardware to test. The chip models and pertinent revisions are as follows: 1. BCM4306 Rev 2 with PHY Analog 1 Rev 2 and 2050 Radio Rev 2. (PCMCIA) 2. BCM4318 Rev 2 with PHY Analog 3 Rev 7 and 2050 Radio Rev 8. (PCMCIA) 3. BCM4311 Rev 1 with PHY Analog 4 Rev 8 and 2050 Radio Rev 2. (mini-PCIe card) Performance testing is accomplished using Iperf with the server connected to my Linksys WRT54G V5 AP/router via a 100 BaseTX wired connection. If I boot Windows XP and run Iperf from it, I get 19.5 Mbs reported. As the Iperf results show considerable jitter, I always run at least 5 trials and report the maximum. The distance from my test computer to the AP is approximately 2m. All bcm43xx tests were done with the latest patches applied. Each interface was tested at rates set from 11 to 48 Mbs with the resulting measured transmission rate show below: Rate Set 11 18 24 36 48 ---------------------------------------------------- 4306 4.65 3.34 6.64 3.48 2.34 4318 6.12 9.86 11.8 14.6 16.2 4311 5.83 9.19 10.8 12.9 3.08 The improvement over a couple of weeks ago is remarkable. The latest tweaks to the specifications have been very beneficial. Thanks again to Joe Jezak. Note that the 4318, which used to have the worst performance, is now clipping along with performance more than 80% of the Windows driver written with full access to the hardware specs. The old 4306 with a PHY Rev 1 still needs the most work. A second part of my test procedure is to use a Wi-Spy 2.4 GHz spectrum analyzer (http://metageek.net) and their Chanalyzer 2.0 software to look at the output from the various radios at a distance of about 1.8 m. The results show the following: Card Amplitude at 1.8 m with rate=24 Mbs --------------------------------------------------- 4306 -50 to -60 dBm 4318 -60 to -70 dBm 4311 -55 to -65 dBm I'm surprised that amplitude of signal does not correlate with performance; however, the 4311 amplitude does diminish a lot at the 48 Mbs rate, which probably explains the falloff in performance at that rate. In addition, the 4306 showed a much poorer separation of the individual subchannels in the spectrum. Larry _______________________________________________ Bcm43xx-dev mailing list [email protected] https://lists.berlios.de/mailman/listinfo/bcm43xx-dev
