|This is not so much about OEM vs custom built as it is about configuring your system properly for best performance. Adding more RAM will only improve performance if your system doesn't have enough memory in the 1st place. Too many people think 'more is better'....if 2GB is fast, 4GB will be faster, 8GB will be even faster. But that is not necessarily the case. After a certain point, you will see little or no difference...it's called the 'law of diminishing returns'.|
Also, you generally need either 2 or 4 sticks for dual channel mode to kick in. Very few boards will enable dual channel mode when 3 sticks are installed. That means you will only be running with 50% of the potential memory bandwidth with 3 sticks.
And if the Wintec RAM is so-called 'gaming memory', it more than likely requires a higher voltage than the Crucial RAM. If the Crucial voltage requirement overrides the Wintec voltage requirement, the Wintec RAM will be undervolted & that *may* be what's causing problems. That's why it's very important to carefully match your RAM. And it's even more important with an OEM system because you don't have the ability to properly tweak the BIOS settings.