HD5870 DisplayPort or HDMI? CF with 4890?

[PUN]

I have two questions:

1) Is there an advantage of using DP over HDMI? My 3008WFP is currently mounted and I rather not lift and connect (although it's only a minute job)

2) If I use another 4890 with 5870, will I be utilizing all the latest feature of 5870?
I know the performance will scale down to 4890x2, but I'd like to give it a try before unloading 4890.

Thanks

 

[lavaheadache]

you can't crossfire a 4890 and a 5870.

 

[blanketyblank]

There really should really be no difference since both are digital outputs. DP 1.2 is capable of higher bandwidth than hdmi 1.3 so the cords should generally be better though they are more expensive. Thus as long as you aren't experiencing problems like sparkling via hdmi you're fine. Otherwise you should get a better HDMI cable (thicker and/or shorter) or switch to a DPI cable.