I've tried playing Crash Bandicoot 2 on the "Sony PS1 Emulator for PS2" (aka POPS,
LBB-00001) using an USB drive as storage medium for the game on a
SCPH-50004 fat PS2. It was playable but execution was somewhat slower than standard.
Using a fat PS3 HDD attached with an unofficial network port → SATA adapter as storage medium hasn't increased the performance.
Maybe with an SSD?