HDX card = 3 to 7 x Accel card? Avid needs to explain.

[ggegan]

Previously I had been told by a sales person that the processing power of an HDX card would be the equivalent of a TDM HD5, however, I now see advertisements that state the processing power would be between 3 and 7 times that of an Accel card, which makes 5x an average estimate.

I don't understand why the processing power has such a broad range. What type of configuration would result in 3x as opposed to 7x? If it turns out to be closer to 3x, then buying 2 HDX cards would mean that you would have 512 voices, yet only the processing power of a TDM HD6. From my experience, a TDM HD6 can easily be pushed to the limit for film mixing with only 192 voices, so this would be a woefully underpowered system. If the power is closer to 7x, then that seems to be a better matchup for 256 voices, but 7x is the high end of the range.

What is reasonable to expect and what are the factors that determine where a system would fall within the processing power range? I need a comprehensive official explanation from an Avid rep before I can even consider an investment in HDX.