ACCELL UltraAV USB 2 to HDMI Adapter Provides an Easy HDMI Connection

The ACCELL UltraAV USB 2.0 to HDMI Adapter allows Mac and Windows users to send audio and video to an HDMI display by connecting it to a USB port. The convenience of this solution versus others is that one doesn’t need to connect to separate audio and video sources to produce an HDMI signal; all of the data is sent via USB.

Testing System and Methodology

We tested this device on two Macs.

  • A MacBook Pro Early 2008 running Mac OS X 10.7.3 and 6 GB of RAM, with 2.6 GHz Core 2 Duo processor.
  • A Mac mini Late 2009 running Mac OS X 10.6.8 and 8 GB of RAM with a 2.4 GHz Core 2 Duo processor.

The atMonitor app was used to measure FPS (frames per second) and processor utilization. A Samsung LN-S4092D LCD TV, connected to a Sony STR-DH510 receiver, was used for HDMI output. The TV has a native resolution of 1368 x 768 pixels. Video performance will be compared to the built-in LCD screen (1440 x 900) and a connection to the TV’s VGA port via a DVI to VGA adapter (1024 x 768) on the MacBook Pro, and to a direct HDMI connection and a HDMI to DVI adapter (1024 x 768) on the Mac mini.


After struggling with the blister pack, we retrieved the adapter, a 22-in. USB to mini-USB cable, a Quick Start Guide, a CD with a software driver, instructions and release notes. Although the documentation and website only claim compatibility with Mac OS X 10.4 - 10.6, we were told the product is also compatible with Mac OS X 10.7. Unfortunately, the enclosed CD is a mini-CD, whose 80 mm form factor can’t be used in the slot-load CD drive in our MacBook Pro and Mac mini.

ACCELL UltraAV USB 2.0 to HDMI Adapter

We went to the product page to see if a download was available, but couldn’t find one.  We went to the support section of the web page, couldn’t find any relevant articles, and sent an email to support, whose claim is to respond within 24 hours.  We also reviewed the documentation, which suggested we go to to download the latest driver.  We did this, and downloaded the DisplayLink 1.7 installer.  However, upon running the installer on our Lion machine, it warned us that “The disk you chose contains a newer version of the software you are installing. Installing this software will replace a newer version with an older version.”  Since this didn’t sound like a great idea, we decided to try and plug the device into our Mac anyway.  Although the documentation warns that one shouldn’t do this until installing the driver, since it appeared the driver was already present, we proceeded. Unfortunately, the device didn’t seem to be recognized, only showing up as  a “USB to HDMI Adapter” in our Sound | Output System Preference, and offering no additional options in our display’s System Preference.

Once we received a response (after the 24 hour benchmark, but a thorough response) we were told to install the driver, despite the error message.  After this, once we plugged the unit into our MacBook Pro, we were offered an additional display, the display System Preference showing a single resolution choice of 1280 x 720. Using SwitchResX, we found additional resolutions of 720 x 480 and 640 x 480 available.  Installing the driver on our Mac mini running Mac OS X 10.6.8 did not produce any error messages.


We measured performance by playing a 720p QuickTime movie trailer downloaded from the Apple Movie Trailers site.  Men in Black 3, to be specific.

MacBook Pro Performance

Mac mini Performance

Note : atMonitor displayed 0 for Mac mini USB to HDMI FPS, so we estimated this figure based on processor utilization and comparing viewing experience to same on the MacBook Pro


One issue we noticed when trying to use the extra screen as our desktop is that the menu bar and dock weren’t entirely visible. This is due to a phenomenon with many HDTVs referred to as overscan, and is really a problem with the TV, not the computer, though some computer implementations try to address this issue. This article goes into detail about this.

When connecting our Mac mini directly to our HDMI-equipped TV, the Displays System Preference offered an Underscan slider. Similarly, reviewing the documentation for the PC version of the DisplayLink driver revealed a Fit to TV option. Newer TVs may also offer a way to address this issue, with modes such as Screen Fit (Samsung) or Dot by Dot (Pioneer) but our TV did not. Some have tried to create custom resolutions with tools such as SwitchResX or DisplayConfigX, but we were unsuccessful.  A query on the DisplayLink Forum has so far gone unanswered.


The ACCELL UltraAV USB 2.0 to HDMI Adapter provides a quick, easy way to connect an HDMI device to your Mac, requiring a simple driver installation, and then plugging the adapter into an available USB 2.0 port. Performance was not quite on par with other solution when high-speed video was involved, but is perfectly acceptable for everyday use.  Use as a primary display for those TVs that suffer from overscan and don’t offer a way to address it in the TV is problematic, since both Mac OS X and the PC DisplayLink driver offer ways to deal with this, but this is more the fault of the driver, and perhaps the OS, than the device.  For those that quickly need to connect an HDMI device to their Mac, this is a solid solution.


Product: UltraAV® USB 2.0 to HDMI Adapter

Company: ACCELL

List Price: US$99.99

Vendor Price: US$77.24

  • Processor: 1.2GHz or higher Windows XP (2GHz or higher 7 or Vista), Dual-Core (Mac) 
  • Memory: 512MB
  • Free Disk Space: 30MB 
  • USB Port: Yes 

Windows: Windows 7 (64bit or 32bit), Windows Vista (64bit or 32bit), Windows XP (32bit) 

Macintosh: Lion 10.7, Snow Leopard 10.6, Leopard 10.5, Tiger 10.4



Very easy to send both audio and video to HDMI device. No external power required — powered by USB bus.


No provision for dealing with overscan. Slightly degraded performance when dealing with high-speed video.