The updated specs allow transfer speeds of up to 4 GB/s, which is essentially half of what computer PCIe NVMe SSDs can achieve, since the SD cards are only limited to X2 lanes instead of X4. Nevertheless, with the new version, upcoming SD Express and microSD Express cards can easily handle 4K and 8K video recording without compression.
https://www.notebookcheck.net/SD-Express-8-0-specs-released-4-GB-s-transfer-speeds-now-possible-for-SD-cards.466063.0.html