MBA 4,2 Ethernet adapter / CF card problem

Aside from irregularly occurring freezes (maybe Safari related?) there's this oddity: when Apple's Ethernet adapter is plugged in, the other USB port will not read a CF card, no matter whether one of my two card readers (yes, both working ok with older MBP) is plugged in or the camera is connected directly (Olympus E-types).
TNX for pointers!

 

It is an MBA mid-2011. It has, as mentioned, some other quirks too. Can freeze and does so when Safari is open. Safari has display issues (text on top of text) but Safari need not be the cause of the freezes, tho with other browsers and Safari off, so far no freeze observed. Find it hard to track, all a guessing game. Anyway, it appears not to be the powered USB hub, freezes occur with or without the hub connected. - So, one puts up with quirks and finds the machine otherwise pretty nice …

 

Energy Saver settings!

Further to the the var. & sundry quirks with this mid-2011 MBA 13" ... I read about changing the Energy Saver settings and simply moved the slider to 'Never' for the computer and unchecked 'Put hard disk(s) to sleep when possible'. No more freezes, no problems waking from sleep (well, it doesn't) and after repeated 'Repairs' (Apple's own, DiskWarrior, Drive Genius) the USB connected items properly show up, e.g. a CF card in a reader or inside the camera. - Someone here explained (PC user), well, there's maintenance going on and if going to sleep happens during such a 'house keeping' task, things drop into an unending loop and one has to force a shut down and restart. I understand too little of these matters, all I can see is the result of suppressing the computer's going to sleep. As it has solid storage, not a spinning hard drive, this seems of little consequence (does not seem any warmer than observed before).

 

MBA & CF card

Last word wrt Energy Saver settings:
Apple support waded me thru some fixes (SMC reset, more). Afterwards and according to recommendations I set short display sleep time (my choice 8 min) and short computer sleep time (my choice 12 min) and left putting hard disks to sleep unchecked. -- Things improved markedly!