🚀 go-pugleaf

Hey, folks.  I have a couple of minor mysteries that I need help solving.

1st (the main one):

I upgraded from an 8086-10 to a 386DX-40.  When I bought the AT, I didn't get a
hard drive or monitor, so I used the ones from the XT.  The HD is some type
of Seagate that has a 21Mb capacity.  Here's the weird part.  On the XT, the
optimal interleave was 1:3, but on my AT it is now 1:6!!!  The controller for
the HD is an 8-bit card (same one from the XT), and it's plugged into a 16-bit
slot (that's all I have).  Any suggestions on how to get my 1:3 (at least)
interleave back?  BTW, I used Norton 6.0's calibrate program for calculating
and changing the interleave, and I run with a 64K memory cache.


2nd mystery:

  My 386 has an option in the CMOS setup program that isn't documented in the
manual.  It's called "Decouple Refresh Option" and it's setting are "Enabled"
and (of course) "Disabled".  When it is enabled, the speed of my machine
increases by about 0.3 mips (as shown by MIPS.COMv1.2) faster than with it
disabled.  Any clue what is going on here?

  Hint:  When I first got the machine, I only had 1 (of 4) if my SIMM banks
filled. (I have 4 banks, each containing 4 slots)  When this option was
enabled, the machine would occasionally freeze up, so I stopped using it.  
However, when I added more SIMMS (I filled up the other 3 banks), the machine
no longer froze up when it was enables, so (naturally) I use it.

P.S. -- My motherbord is of the "Vega 386 Cache Series" (as if this would
        help much ;-)

Any (and all) help is welcome and appreciated.  Please reply by email, as I 
can't afford the time to wade through all the posts on these groups.

Thanks a bunch!
-- Geoff