These are the only DDR2 dims I have found in my stash thus far. They are super zoomie 5-5-5's.
They will down-clock to slower speed with improved latencies btw.
Don't know about that Gateway box, but that standard MSI mobo will accept up to 800's in dual channel mode.
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There are a ton of these OCZ dual channel kits on eBoy, used, for less than $20 with free shipping - at various speeds and as 2 x 1GB dimm kits.
Looking in a few other places now ...