I have a mid-2010 27" iMac with a second Apple 27" display. I have been using a Diamond DisplayLink BVU195 adapter to drive a third Dell 2709W monitor over USB2 in portrait mode at 1200x1920.
I have two questions about the benefits of the DL-3X00 hardware:
1. Can someone please tell me if there is an advantage to using a DL-3X00 device on a USB2 Mac like this? If I used a StarTech DisplayPort DL-3500 adapter or Diamond DL-3900 DV100 adapter, does it provide optimized video speed over a DL-195 device over USB2? Is there any advantage to upgrading using the same 1920x1200 monitor?
2. From what I understand, DL-3X00 devices allow resolutions up to 2560x1600. So instead of a Dell 2709W at 1920x1200, you could run a Dell U2711 or U2713 at 2560x1440 or U3011 or 2560x1600. For those of us stuck with USB2, is this the only advantage to upgrading to DL-3X00 chipset devices?
I've also experienced two issues with the alpha drivers:
1. Rotation works perfectly with the new 2.0a2 drivers. But I still get lots of display flickering when showing video or HTML5 content in Safari --
http://www.icloud.com is a perfect epileptic test for the flickering. It's all over the place using Safari, but doesn't happen in Firefox. This seems to be a known issue that may be fixed when 10.8.3 is released.
2. I see some horizontal screen stretching issues like the previous poster. See the attached image where the "r" in Worldwide and "m" in espn.com are stretched by one pixel. This happens in Firefox, but not Safari. Strange. This screen stretching behavior also happens when using Snapz Pro 2.5 -- the DisplayLink screen literally "jumps" and stretches 20 pixels horizontally when doing a screen capture.
Thanks for releasing this new 2.0 alpha -- you may hear a lot of complaints here, but the fact that I can run a third monitor over USB has helped extend the life of my mid-2010 iMac. It's been a great addition and I'm glad you continue to update the drivers.