Integrated HD video problems (sometimes turns off for a few secs)

[idata]

Hi, I hope you can help me with this 'cause I've been up and down the internet (saw even the darkest sewers) and can't find a solution.

Here's my problem: I'm running Win7 x32 on my Acer aspire X3900 (custom install - downgraded from x64 because of some Hauppauge TV Tuner driver requirements). The video (using the HDMI port on the integrated Intel HD graphics) sometimes turns black for one or two seconds and then goes back on. It doesn't just turn black, it's the deep black kind as if there's no signal. This behaviour is intermittent; i.e. sometimes it takes hours before it does this only once, sometimes it happens every other minute for a few minutes in a row. I've changed the BIOS to give it more memory by default (changed it to 128MB), but that did not help. AFAIK I'm using the latest Intel drivers - 8.15.10.2189. What to do to solve this? I'm really stuck here Thanks in advance for any help!

[idata]

Forgot to mention: Switching DVMT to fixed with a fixed memory of 256 MB does not change anything.

It appears even that the memory is still allocated dynamically. Right after booting it uses 38MB memory, while the minimum setting in BIOS is set to 128MB allocated..