I have a FX 8350 installed in a GA-990FXA-UD3 motherboard, revision 1.1. 16 GB G.SKILL Ripjaws X Series 16GB (4 x 4GB) 240-Pin DDR3 SDRAM DDR3 1866 (PC3 14900) Desktop Memory Model F3-14900CL9Q-16GBXL memory installed. All memory modules test good but modules installed in slots 1 and 3 report 2 GB instead of 4. Problem started about one month after installing new CPU. Gigabyte says check with old CPU, it was sold, any ideas here.
Have you switched the RAM in the DIMM slots to see if the under reported size DIMMs change with the DIMM location or if they stay with slots 1 & 3 ? I'm guessing it's a mobo issue as I've never seen an AMD or Intel CPU that couldn't properly read the DIMM quantity unless the DIMM was bad.
Yea first thing I did. Thought I was using no. 1 slot turned out to be no. 4 slot. All four sticks posted 4 GB. Switched slots and slots 1 and 3 wouldn't even post to bios. Was leaning toward mobo problem but Gigabyte insist it's CPU problem. They wanted me to test it with old CPU and didn't hear I sold it, lol
Thanks for reply
Do you have a local PC repair shop that would charge you a modest fee to drop another CPU into the mobo?
My personal experience with Gigabyte support is they refuse to acknowledged known product defects. I do however like their "Durable" series mobos and have used quite a few of them. Unfortunately they had some serious VRM issues with the original FX mobos and 8000 series FX processors because the VRM was not designed to power 8-core FX CPUs which draw a lot of electrical power. The FX-9000 models actual require a special mobo designed for the 220w TDP. Many people are unaware of this issue and find problems when using FX-9000 CPUs in mobos that work fine with FX-8000 series CPUs.
Only in the last year of so did Gigabyte update the mobo designs on the FX model mobos to provide proper power to AMD 8-core CPUs without VRM overheating and resultant drops in CPU frequency. For two years Gigabyte Tech Support tried to convince me the VRM issues were insignificant until consumers started returning the mobos and buying other brands... I would definitely consider using the later "FXA" model Ultra Durable series mobos with the updated VRM designs, but in good conscience I can't recommend the earlier Gigabyte FX mobos for anything but a quad core CPU.