Add notes on Penta SATA HAT.

Author: geerlingguy

_hats/radxa-penta-sata-hat.md

@@ -12,4 +12,13 @@ This HAT includes four SATA drive connectors, plus one edge connector for a 5th
 
 There's also an 'Expansion interface' with connections for OLED and Fan control, but there is no included adapter for such purposes. So you'd probably want to connect a little fan to the Pi's fan header for the Pi itself, or a USB fan for the drives, if needed.
 
-It looks like the SATA controller is a JMB585 PCIe Gen 3x2 SATA controller, so it could benefit from running the Pi 5's PCIe lane at Gen 3.0 speeds (setting dtparam=pciex1_gen=3 in /boot/firmware/config.txt).
+It looks like the SATA controller is a JMB585 PCIe Gen 3x2 SATA controller, so it benefits from running the Pi 5's PCIe lane at Gen 3.0 speeds.
+
+To use the board at Gen 3.0 speeds, after connecting it to the Pi, you need to add the following lines to `/boot/firmware/config.txt`:
+
+```
+dtparam=pciex1
+dtparam=pciex1_gen=3
+```
+
+I was able to get sequential read speeds around 800-850 MB/sec with an array of four Samsung QVO SSDs set up in RAID 0.