Question PC3-12800U & PC3-12800E

[rhyde]

Hey guys, i have PC3-12800U & PC3-12800E RAM, Both are 4GB each. My CPU is Xeon X3430, my motherboard is Asrock H55M-LE. CPUz is shown 8GB RAm Installed. But why am i feeling my PC is really slow after i put the PC3-12800U? FIrst i have only the PC3-12800E. Thank you in advance

 

[Eximo]

Mixing memory usually ends up with the system defaulting to the slowest supported memory speed. You may need to change the setting in the BIOS.

If this is an OEM board, that might not be possible and you will need to purchase memory that is an exact match.