BSOD, nv4_disp.dll, PAGE_FAULT and other short stories

Hi
after few weeks of fighting, staying up till 3:00 am in the morning, i was ready to take a sledge hammer and put the box out of its misery.
a hope arrived.
i read few threads on this forum, which put me on a correct path.
here are the machine's specs :
~ AMD Athlon 64 3500+ Processor (Venice)
~ Plextor PX-740A 16X Internal Dual Layer DVD±R/RW CD-R/RW Drive
~ MSI NX7800GT-VT2D256E Geforce 7800GT 256MB 256-bit GDDR3
~ Asus A8N-SLI nForce4 SLI Motherboard
~ 250 GB Maxtor SATA Hard drive
~ Thermaltake Silent PurePower 480W Power supply
~ 1 GB PC 3200 DDR400+ RAM (2x512MB)( GKWITIS )
~ Windows XP Pro ( 32)

checked temps, HD , memory, updated drives and slowly was going insane. the machine would crash -> BSOD with various errors, after playing for few hours fear,cod2, hf2 . it once went down during an installation of a software, some other time while just browsing. finally i read this thread to prep myself for uploading mini-dumps and making sure all the steps have been taken on mine side:
http://www.techspot.com/vb/topic36718.html
after resetting the swap space, it crashed again with :
nv4_disp.dll crashing to BSOD
and luckily for me i came across this thread :
http://www.techspot.com/vb/topic17534.html
so as a last step i switched from dual channel to a single channel.....

guess what ?
problem is gone.

so this is my q :
can i assume that the problem is of running memory at higher speeds in dual channel ( thus corruption ending in BSOD ) or it is still some software driver problem, simply DCH mode itself and drivers associated with it.

if main suspect is memory running DCH mode: is there a point to try running it in DCH at lower speeds ( <400) . in SCH mem is running at 333 and it seems machine is uber -> :)

thanks for any thoughts
k