Just as a test, you might try reducing the bitrate even more, just to see if that reduces the glitches. i.e. try to configure the PS3 to output either 1080i or 720p instead of 1080p. If that helps, then perhaps one of your Redmere cables isn't working as well as it should and its HDMI circuitry is not properly augmenting the high frequency signal.
Another possible cause of dropouts would be a loose connection in a cable or device connector. Vibrations (perhaps due to loud subwoofer output) might be causing intermittent contact, thus causing glitches in the signal. Verify that all of the cables, including speaker cables, are fully seated, tightly fastened, and not subjected to undue torque.
It shouldn't make any difference, but you might try setting the PS3 to output PCM instead of bitstreaming. In principle, it should make no difference in the quality of the sound you hear, but would shift the audio decoding from the HTIB into the PS3. Since the resulting digital audio signal would be uncompressed, it would result in a slight bitrate increase.