unless they were specifically sold to you as dual channel kit, then you can't really.
You can try a couple of things which <i>might</i> help:
<b>1)Relax memory timings</b>
In your BIOS, there are settings for the memory called stuff like CAS, RAS, TRAS, and something else I can't remember atm. basically lower timings=more performance, higher timings = more stability.
set CAS to 3, and the others to something fairly high 4-4-8 maybe?
<b>2)Increase VMEM.</b>
Overclockers frequently have to provide more voltage to parts to make them stable at higher speed. although you're not actually running the RAM faster than it's rated for, you might still find a little extra voltage will help your RAM be stable.
<font color=blue>The problem with increasing Voltage to any component is that it will <i>always</i> result in increased heat output, and a greater chance of frying it. it would also void the warranty if you ran it overvolted (although there is no way they could really prove that you did)</font color=blue> I just thought I'd cover my own a$$ there
. That said, most RAM runs by default at 2.5 or 2.6V (IIRC), and you could maybe try up to 2.7V-2.8V without much risk. Options for changing Memory voltage are also in the BIOS.
I suspect you'll not have any joy with those sticks in dual channel, even if you do try what I said above - the most sensible thing to do is either run in single channel mode (no biggie - 5-10% performance decrease depending on the app - I use a single-channel P4 2.8C system at work and it's very quick still), or pay the extra for some certified dual channel stuff.
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Epox 8RDA+ V1.1 w/ Custom NB HS
Summer's here! so ease off the overclock...
XP1700+ @166x12 (~2Ghz), 1.475 Vcore
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