January 19th 2017 Verified user
Bought two of these to upgrade an older Gigabyte GA-H55M-UD2H with i3-530 from 4 to 8GB. I didn't have to change any BIOS settings at all. Old memory banks out, new ones in and my PC started without any hiccup. Having read through a number of possible compatibility issues with memory on this older board in various forums, I was initially very hesitant to purchase brand new memory, as most feature 512MB chips. At least I believe this is part of the reason why it may not work.
This particular memory, F3-12800CL9S-4GBRL is available in two versions for 4GB: 8 chips with 512MB each, Single Sided SS or 16 chips with 256MB each and Double Sided DS. You will need the latter, 16 x256MB version for the GA-H55M-UDH2. I hope this bit of information will help those, who look for these specific characteristics. You need to contact customer service though, in order to ensure you will get the correct one, because both versions have the same ordering code by the looks of it. Even though the older 4GB (2x2GB) Ripjaws had a faster latency with 8-8-8-24, the additional 4GB (changing to 2x4GB) made a huge difference in performance overall.
5* also for excellent customer service!! Thank you.
Review of 4GB G.Skill DDR3 PC3-12800 Ripjaw Series (9-9-9-24) Single desktop memory module