Re: 4 memory slots- 2 sets of different RAM?
Mixing RAM will work if done right, but it's never recommended because you're not using matched ICs. You want all the sticks to use the same voltage, the same timings, and the same frequency. If one set operates at DDR2 800 and the other set at DDR2 1066, the 1066 will have to run at 800. If the first set runs at 4-4-4-12 and the other at 5-5-5-15, the first set will have to run the relaxed timings of 5-5-5-15.
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