Super User is a question and answer site for computer enthusiasts and power users. It's 100% free, no registration required.

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I recently purchased a new computer and a new flat-panel monitor from Dell. Everything worked perfectly if I used the supplied analog monitor cable. Since both the monitor and the graphics card supported HDMI, I purchased a 6' Dynex HDMI cable and connected that (disconnecting the analog cable, and with the system turned off).

Everything worked fine at first - it auto-detected the change. After a few minutes I noticed the screen would go black for a second or so, then come back on. These dropouts kept happening. Reconnecting and rebooting made no difference. I switched back to analog, and it's been working perfectly.

What are the most likely causes of this, and how can I diagnose the problem?


  • Display adapter: ATI Radeon HD 3450 256MB
  • Monitor: Dell ST2210 Widescreen Flat Panel (1920 x 1080)
  • Cable: Dynex (Best Buy) 6 foot HDMI digital A/V
  • Computer: Dell Inspiron, Intel Core 2 Duo
  • OS: Windows 7 Ultimate 64-bit
share|improve this question
up vote 2 down vote accepted

The problem can be hardware, software or firmware. Too many causes are possible to analyze it like that.

Try to ensure that you have the latest drivers from the Dell support site. You may also try another HDMI cable, just in case.

But if the problem persists, and since this is a new computer, you're entitled to ask Dell Support for a solution.

share|improve this answer

It could be a driver issue. There have been a lot of flakey HDMI issues with older drivers. Try getting the latest direct from

share|improve this answer

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.