OT: x86 Motherboard RAM Sticks

     I have a x86 motherboard (Giga-byte GA-7VKMLS, in another Walmart bo=
x)=20
that doesn't seem to mind two differently sized RAM sticks in A/B order b=
ut=20
becomes intermittent (POST doesn't start 50% of the time at power on) whe=
n in=20
B/A order. That is, if I swap the sticks, it works, and if I swap them ba=
ck,=20
it is intermittent. The MOBO book says mixing sizes is Okay but obviously=
=20
something is going on.
     The two sticks are marked:
Value RAM, KVR-PC133/256, 3.3v, Kingston
Value RAM, KVR133x64c3/128, 3.3v, Kingston
     Anyone recognize if I'm doing a No-No
     TIA