The VisionFive 2 is currently the best RISC-V SBC option, at least until TH1520 becomes available (next month?), depending on the price.
I can vouch for the VF2 hardware - works well. Alas PCIe is oddly slow, but I'm hopeful that firmware will improve that.
EDIT: The Pine Star64 is (should be) the exact same SOC, so it should be basically the same as VF2 (small differences like PCIe edge connector instead of an M.2 slot, etc).
And, yes, with its OoO CPU cores it should match a Pi 4 at the same MHz, but do more MHz.
It's probably being limited because the RAM to RAM copy speed isn't much more than that! I get 475 MB/s memcpy() speed for 64 MB copies on my VisionFive 2. The much slower CPU on the AllWinner D1 manages 1100 MB/s n the same code. Somehow the SiFive-based SoCs have never been good on RAM speed -- the HiFive Unleashed and Unmatched were even worse than this.
Hopefully the Horse Creek SoC has some good Intel DDR IP in it.
Horse Creek would be nice - should it ever become available for purchase.
EDIT: Well, I'm shocked. With a far more beefy supply (12.3V/0.7A) I now hit 295+ MB/s, not great but so much better than before. Thanks for the hint.
What is the rating of your bigger supply?
And presumably what you were measuring is the average Amps/Watts, not the peak.
If you follow the "Where to Buy" links for the United States, it's available from Amazon for $280.
[1] https://www.amazon.com/ASUS-Tinker-1-5GHz-Graphics-Motherboa...
[2] https://tinker-board.asus.com/product/tinker-edge-t.html