That is the 64 million dollar question. Personally, I doubt they would have made significant strides at the chip level when it comes to native contrast. However they will have bound to have implemented few methods to compensate.
In light of that, would the compensatory methods used give acceptable results. A clue would be how the buyers of the RS4500 'see' their projector perform. They seem quite happy. Only one or two wish the native contrast was better.
Native contrast with the native 4k chips will steadily get better over time, but it will take some time, so I put my money where my thoughts are and bought a RS640/X9900 courtesy of Javs. I've been spoilt with a native contrast of in excess of 100,000:1 with my current JVC -15, small 2.4 gain 106" screen.
I'm hoping I did the right thing. In 9 more days, I'll know, either I'll kick my self or congratulate myself
, if I'm wrong it won't be too bad, I'll enjoy this unit for a few years and upgrade down the track when the 4k chip is more mature and laser engines have ditched the phosphor wheel.
Always wondered about the phosphor wheel, does it continue to emit light for several milliseconds after the laser power is cut?