Hello.
I'm trying to get the most out of my 486 setup but some settings elude me, and I'm sure also elude others as well.
What is the fastest setting and what is considered optimal (fast but stable) ?

• Slow Refresh (1/4 Freq) = Reduces refresh period frequency (64ns instead of 16ns) to conflict less with CPU activities and increase performance. Requires RAM that can retain data longer between refresh cycles or you'll get data corruption.
  
• PCI Bus Park Option = You can use this option to specify whether a PCI unit is allowed to "park" on the PCI bus. Which PCI unit receives access to the bus for I/O work is basically decided by the PCI controller. If you have activated the option, then a PCI unit gets the exclusive right on the bus at short notice.
• PCI Posted Memory Write = Enabling this option will buffer the data transfers from the PCI bus before main memory accesses the info. Data is transmitted in a more concentrated way to avoid delays.
• Preempt PCI Master Option = When the option is enabled ("Enabled"), read / write operations on the PCI bus (even if a "master" device), can be interrupted by certain system operations. For example, memory refresh; otherwise, "unplanned" parallel operation of various system components can be performed, which can lead to system failures, and at worst, data loss.
• IBC DEVSEL# Decoding = This option allows you to set the decoding type used by the IBC (ISA Bridge Controller) to determine the selected device. The longer the decoding cycle lasts, the higher the chance of correct decoding of commands. The following values ​​are selected for selection: "Fast", "Medium" and "Slow" (default).
• System BIOS Cacheable = Enables or Disables the cacheing of the system BIOS ROM at F000h-FFFFh inside the L2 cache.
• Video BIOS Cacheable = Enables or Disables the cacheing of the video BIOS ROM at C000h-C7FFh inside the L2 cache.

The last two are especially confusing to me since the BIOS already has the option to "Shadow" the VGA BIOS. Why would caching it make any considerable difference ?
Pretty much every answer I have seen on the web is a waste of time since the answer always is, "its faster so enable it" with no clear explanation of how or why this would be faster.
Most games don't use BIOS calls for video access, so caching the video bios seems like a waste of system cache.
And as for cached system BIOS calls, maybe there could be some benefit...

Thanks