I have a few suggestions.
1. Remove that USB3.0 card, you are loosing massive amounts of performance even worse than a USB2.0 card. This is due to how heavy weight the usb bus drivers are.
The front side bus on that board is capped at 100 or 133mb/s (depending on bus speed) so it’s pointless the usb is capped anyway. Search some threads over at Vogons regarding USB card slowdown.
Better to transfer over LAN.
2. Best OS is Windows 98SE or Win2000 SP4. Windows 7 is not going to work on a P3, it will blue screen and stop booting after the first set of updates due to no SSE2 instructions. I recommend buying Oscar’s AGP to PCI-Express adapter if you want to run Windows 7.
3. Ditch the SATA PCI card. Startech make a quality ide to sata adapter that supports ATA133. You will free up IRQs and not flood the pci bus as again it’s only capable of 133mb/s. I run a Samsung 120GB SSD on one of these adapters and it flys along on my Epox 8K3A VIA ATA100.