joncampbell123/dosbox-x

All IO operations with IMG-es are extremely slow when booted into Windows 9X

Opened this issue · 3 comments

rayrapetyan commented

Question

I’ve followed the “Installing Windows 9x” instructions and successfully set up a working system. However, all disk operations (e.g., copying to/from mounted IMG HDD/CDs) are extremely slow, resembling the performance of a 2x CD-ROM drive and old HDDs. The CPU usage remains low, suggesting an artificial speed reduction. Is there a way to increase IO operations for IMG volumes in DOSBox-X?

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joncampbell123 commented

set "hard drive data limit=0" under the [dos] section to disable the limit.

The default setting -1 attempts to recreate the disk throughput of mid 1990s 386/486/Pentium era hardware.

rayrapetyan commented

Unfortunately, this option doesn't work (it is mentioned in the Installing Windows 9X tutorial, and I have been using it from the start). Adding more details:

  1. From Windows 95, copying a 40MB file from one mounted image to another takes approximately 35 seconds (same operation in DOS takes 6 seconds).
  2. Windows 95 benchmark results:
    image
    image
    image

Average CPU core usage during benchmark: 30%.

joncampbell123 commented

Then this is an issue with IDE emulation, which is completely different from INT 21h file/disk I/O emulation.