The only thing I added was an interface board, a 1TB NVMe M.2 SSD, and an aluminum heat sink to be installed in the PCI-e x1 expansion slot. Since it is a PCI-e x1 expansion slot, the speed is limited. There is no free onboard M.2 socket, so it can't be helped. The Western Digital NVMe M.2 SSD 1TB 3200 MB/s operates at a much slower speed of about 900 MB/s. Still, it's faster than a SATA 2.5" SSD.

This PC-5, which I use on a daily basis, is installed on the far right side, closest to me. A PC switch (black) will also be installed on top of the PC case, so a thin portable Blu-ray drive (white) with USB connection is installed. The leftmost PC case is in its old state before the update.

The new PC case is also very quiet. The new PC case has six 120mm fans, including the CPU fan, and one 80mm HDD fan installed, but for daily use the fan speed is controlled to around 600-800 rpm, so you can hardly hear them rotating.

This time, I'm updating PC-5, which I currently use on a daily basis (it has the highest operating rate).