Fatal1ty 990FX Professional Memory Quesation

[flayologist]

thinking of purchasing the Fatal1ty 990FX Professional, and will use it with a AMD Zambezi 6100 AM3+ 6 core processor (FD6100WMGUSBX). I also want to use the CORSAIR XMS 4GB (2 x 2GB) 240-Pin DDR3 SDRAM DDR3 2000 (PC3 16000) Desktop Memory Model CMX4GX3M2B2000C9 with it. Was wondering if any one has tried to use 2000 mhz OC memory with this board and if it worked or not?

[AMD4Me]

Re: Fatal1ty 990FX Professional Memory Quesation

There are two basic issues with RAM that determine if it will run as you desire.

The first is mobo compatibility. Most but not all DDR3 RAM will work in most DDR3 based mobos. In theory ALL DDR3 RAM should work but because of nuances in DRAM and mobo manufacturing, occasionally there is a compatibility issue.

FYI- Corsair has a website DRAM selector that lists some of the DRAM they have tested and confirmed to work on specific model mobos/PC systems/laptops. This may help you confirm compatibility. If not you can always e-mail Corsair Tech Support and also Asrock Tech support to get confirmation - if the specific RAM you desire to use is not already on the QVL list. Most QVL list are out of date and only a sampling of a few DIMMs tested when the mobo was first released so it is NOT the end all or be all in RAM compatibility.

The second issue with RAM is what speed it will function at without issue. Different model CPUs can have different design default RAM frequencies. As an example Deneb and Thuban by default operate at 1333 MHz. and Zambezi at 1866 MHz. When you purchase/install RAM that has been tested and confirmed to be "capable" of operating at 2000 MHz., it does NOT mean that your CPU is capable of running the RAM at that frequency if your CPU is designed to run the RAM at a lower default frequency. In many cases the CPU will run the RAM at a higher than default frequency, but this can be substantially less than what the RAM is rated at. Denebs typically make it to ~1600 MHz.; Thubans to ~1800 MHz. and Zambezi 2000+ MHz.

It's also worth noting that some mobos automatically default the RAM frequency to the CPU RAM stated frequency when all DIMM slots are populated. In cases like this no matter what you do you will not be able to OC the RAM as the BIOS blocks this option. AMD has also noteded that only (2) DIMMs are assured to run at 1866 MHz. or higher on Zambezi CPUs but many folks have no issue with (4) DIMMs at or higher than 1866 MHz.

*** In cases where you discover RAM incompatibility you should notify Asrock (or whatever mobo brand that you are using) and the RAM maker so the next BIOS update can address and resolve the issue.

Flayologist - Even though you may be aware of the above info, I posted a detailed reply as I thought it may be useful for other forum members who are not aware of this info.