I have been testing hard drive performance on my P4 test rig with CrystalDiskMark v2.2 and have come to very odd results in Win98SE with the 32-bit protected-mode driver deactivated:

CrystalDiskMark reports ridiculously high read speeds, and sequential writing is also suspiciously high.

I have benchmarked the drive with the following configurations:

1. Win7 SP1 - DMA Mode 5 active
2. WinXP SP3 - DMA Mode 5 active
3. Win98SE - 32-bit protected-mode Vxd drivers - DMA (level unknown, probably 5) active
4. Win98SE - protected mode drivers deactivated - MS-DOS Compatibility Mode - strange results

Specs:

Asus P4b533-E - ICH4
Pentium 4 2.8 GHz Northwood
1.25 GB DDR
GeForce4 Ti 4200 128MB
Floppy Drive 1.44MB
DVD-ROM
Samsung Sv1604n 160gb HDD

Windows 98 SE on 30gb Primary Partition
RLOEW's PATCHMEM and PATCHATA installed

Images:
https://imgur.com/a/i4MpyjL

Results seem to be practically same with NT-based OS's XP and 7 - 98SE has slightly slower results within margin, but not any noticeable difference.

Deactivating the 32-bit protected-mode driver (ESDI_506.PDR) causes ridiculous, obviously unrealistic results.

Read speeds of 300+mb/s are obviously impossible, as it is an HDD which is also limited to UDMA-5 / ATA-100.

I was wondering what could be causing these weird results. Maybe somebody else has had similar experiences?