upgrade problem

i have a pqi dual channel ddr 3200 installed right now, cl 2.5 and i added a corsair twinx dual channel kit at 512 mbs cl 2. when the two sets are used in conjunction the machine will not boot into windows, but when used sepratley both pqi and corsair work fine. any ideas

are u setting the timings to the highest rated cas latency?. or maybe u have the mb set to auto in which case its trying to run at a lower cas, which causes probs for one of the sets.. try 3.3.3.8 and see what happens...

k, i tried your timings, no help so then i tried to remove one moduale of both pqi and corsair to get 512 in single channel and this works with some more agressive timings of 2.5 -3-3-6, Finally i tried sticking the moduales into a singal channel configuration and that works, so it won't work in dual channel config

Have you tried dual channel with one of each type of RAM in each channel and both of the higher latency sticks closer to the CPU (than the other stick in the channel)?

yeah, i tied both diff types in both channels, than for nothing better i mixed the ram chips. allwell i'll return them, could just be incompatable dimms