The magic is not by Asrock, but by Intel themselves. They have already told the world that on the H, P and U series 13th gen chips will support DP2.1 on TB4 when paired with a Hayden Bridge Re-Timer. Asrock is just implementing Intels magic.
Not so fast. Devil is always in details. Intel has never told us how this solution is meant to work. Intel
only provided Hayden Bridge JHL9040R retimer component for DP 2.1. As you can see on the diagram you posted, CPU has native support for DP 1.4a HBR3 signals up to 32 Gbps. Intel's website also shows this for CPUs.
Moreover, Intel did not advertise at CES that DP 2.1 on 13th Gen CPUs are pending VESA's certification for DP 2.1, which suggests that CPU itself cannot be certified. For DP 2.1 to work from iGPU, we need either native support for UHBR signal, or a few other components outside of CPU, in addition to the retimer.
1.
video signal from CPU - Raptor Lake doesn't have native DP 2.1, unlike Rembrandt, Raphael and Phoenix CPUs and APUs - so, DP 2.1 is not from CPU
2.
PCON - this chip could convert HDMI 2.1 FRL into DP 2.1 to bring UHBR10 signal at 40 Gbps - RPL CPU does't have native FRL, so not a PCON
2.
redriver - such as Texas Instruments SN65DP141 DisplayPort Linear Redriver for link training and amplification -
1300/D5 BOX might have this or similar chip
3.
retimer - Intel provides Hayden Bridge chip to recover DP 2.1 signal and retransmit it towards USB4 port in systems with longer traces
VESA can certify either a single component as DP 2.1 compliant, such as Rembrandt APU that has 40 Gbps native output since last year, or a motherboard/system, such as the one inside NUC 1300/D5 BOX. Therefore, Intel does seem to do any "magic" here in terms of DP 2.1, but it provides one retimer chip as optional transitional solution that enhances Thunderbolt 4 until delayed Thunderbolt 5 is released, which could happen
after Meteor Lake CPUs. Also, Thunderbolt 4 is certified for DP 1.4 signals and although it could provide DP 2.1 through its 40 Gbps port, TB4 can never be certified by VESA as DP 2.1 device.
So, this seems to be a hybrid solution for Intel for time-being. Intel was left behind after USB4 advancements to integrate DP 2.1. USB4 is more flexible here, as those ports can simply take native UHBR signal from AMD's CPUs and transmit at 40 Gbps.
@crazyeyesreaper
That's why I requested from the reviewer to ask Asrock to send a sample of
NUC 1300/D5 BOX to test and review. When motherboard is exposed and photographed, we will be able to see all chips on it and solve this DP 2.1 mistery.