Hi Omar,
I'm Jewel with Kingston Technical Support. We actually no longer support the GA-EP45T-UD3LR motherboard as it only supports up to 2Gbit DRAM and the parts compatible with it have all been discontinued. DRAM are the the chips on a memory module. As 2Gbit DRAM is fading away, most of our products are currently manufactured with 4Gbit DRAM. That could be causing the issue with the HyperX memory depending on the components that were used to build it. Outside of that, even when this motherboard was supported we did not support it to have more than 8GB of memory using 2GB memory modules. The motherboard specifications shown on Gigabytes webpage do indicate it supports up to 16GB implying you can use a 4GB module. We found that the Intel P45 chipset can only support up to 16GB using DDR2 memory and that with DDR3 memory it was limited to 8GB. Although that is dated information, from 2008, so bearing that in mind a BIOS update could have changed that fact. I do see there has been one BIOS update that enhanced memory compatibility specifically version F7 dated 01//13/2010, so if you do not have the latest BIOS F10, I would suggest to update it and see what happens. If that does not work the issue is most likely that the memory is just not compatible with your motherboard. For any further assistance, please call us at 1-800-435-0640 (USA and Canada only) M - F 6am - 6pm PT and I or another available Technician will assist you. Please be sure to have the part in question on hand when you call.
Thank you for selecting Kingston as your upgrade partner.