My understanding of FCPX's Dual GPU and Mac pro 2013

I've done test to have these conclusion:
1. for rendering FCPX's effects:
use GPU

2. for rendering picture in picture/dissolve etc...
do not use GPU, can use multi CPU cores(that is why FCPX is faster than FCP7), mainly rely on CPU

3. for playing back 4K:
probably CPU frequency is more important than CPU cores
but FCPX has a bug when playing rendered part, the CPU usage is too high to
make 4K 50p prores playback available at high quality setting
(high performance setting don't make sense, the image is too fuzzy)

so with 4K job, the CPU is much important,
cause
now the 4K projects: maybe MV, documentary film, Sports,
if job is worth using 4K camera and lens like ari UP to shoot,
all the effect may always be done at maya nuke ae, but not FCPX!

even if you shoot 4K XAVC for documentary TV, Sports TV,
what you always render is dissolve, speed change, text, subtitle, etc which are not using GPU
cause I think documentary TV always do the effect with CG but not FCPX too
Sports TV project use not so many effect.

so for 4K the new mac pro 2013 is only stronger when you choose 12cores if
you already has 12cores 3.06Ghz mac pro 51.

now,only aja corvid can make 4k 50p output to a monitor
however, no FCPX driver yet.
so you can't output 4K >30p to a monitor now.
the only way is new mac pro 2013 output to a Sharp 4K TV.
but I don't think the Sharp TV can be used for grading
4k projects always show on screen through projector, Sharp TV has DCI or rec709 color space?
I don't think so.


my think of the apple's official website's :
1. baseline is a mac pro with 1 5880 card

2. optical flow: 2 d700 only 2.6X than 1 5880????
I think maybe 2 gtx680 mac edition can beat the 2 D700!

3. 4k pic-in-pic 4.0X?????
it's just compare SATA 2.0 and PCI-E disk, don't make any sense.
and apple don't say at good quality or at better performance.
I don't think better performance make sense when editing 4K
the prores image is fuzzy only on 25 inch monitor!
what about output to a 65inch 4K TV?

4. 16 channels video 4K pores-mulit cam angles???
i think it must be better performance setting.
with the resolution down , I think a mac pro 5,1 with a fast Raid can do it at that setting also!

for 4K:
even if you downscale 4K to a 50inch HD monitor ,the image looks great
you can't say that 4k image is good.

cause I've alway seen good quality on 50inch HD monitor, but the focus wrong when
using pixel to pixel check.

so , if the FCPX alway do the job at better performance setting for 4K 50p
is the mac pro ready for 4K??