ASUS M5A99FX PRO R2.0 Memory Options

[UberGeek]

Greetings,

Last year I built a system using an ASUS M5A99FX PRO R2.0 Socket AM3+ 990FX ATX motherboard with a FX6300 Six-Core CPU. Unfortunately, I had to drop the project due to a job relocation but would continue where I left off.
From what I recall, the memory controller used on this AMD series was weak. Because of this, the general consensus seemed to indicate a single stick on each channel provided the best performance, which would limit my choice to 2 x 8MB.
At that time the ASUS QVL tests were a bit outdated and the memory listed for G.Skill was no longer available.

Can you help me select the best memory kit for this board from currently available inventory?

In my original notes I had the following 2x8GB kits marked but I don't remember the reasons why:
F3-1866C8D-16GTX (TridentX Series)
F3-2133C9D-16GXH (Ripjaws X Series)
F3-2133C9D-16GTX (TridentX Series)
F3-2400C10D-16GTX (TridentX Series)

[GSKILL TECH]

Any of the first 3 can work great.

DDR3-2133 is near the limit of the CPU, while 2400 may be too high and it will require manual tweaking that you may not like if you do not have extensive overclocking experience.

[UberGeek]

Thanks for the suggestions.

I have no problem configuring timing settings after doing it more than a hundred times on my previous board, an Intel DP45SG Desktop Board which refused to work with anything except used Hynix memory. Tried several Double Sided sticks then two different G.Skill modules recommended on this forum, including numerous timing configs but could never boot out of BIOS.

Got really burned on that one...stuck with the board, a CPU, 2 video cards, and 4 new G.Skill modules which Newegg wouldn't take back. I guess these 1333 DDR3 Ripjaws would work in the ASUS but it's not a very desirable solution.

I just need to make absolutely sure I won't run into major incompatibility problems like this again.

I mentioned the F3-2400C10D-16GTX (TridentX Series) because the ASUS M5A99FX QVL dated 7-10-12 listed 10 DDR3 2400 modules, 5 of them G.Skill. One of these was a 8 GB module as follows: F3-19200CL10Q-32GBZHD(XMP) 32GB(4x8GB) 10-12-12-31 1.65 v. The timings and voltage are identical to the TridentX module above which received rave reviews by magazines and users alike. These included Asus Sabertooth and other FX990 owners.

Correct me if I'm wrong, but I would assume if the (2) 8 GB modules above were installed and BIOS settings left in Auto mode, the ASUS board would drop timings to a default SPD value and run at say 1866, CAS 8. In this scenario, stability would be rock solid, tweaks could be left for a rainy day, and the modules would be more compatible in other boards with recent chipsets. IMHO, not a bad outcome.

[emissary42]

The board was tested with several DDR3-2400 kits, however since the memory controller is part of the CPU, that does not automatically mean every setup can hit that frequency with ease and with four modules even more so. The quality of the IMC varies from one CPU to another, so unless you want to bin CPUs for IMC quality it is safer to go with a lower frequency kit.

The AUTO values for most kits sold today are either DDR3-1600 11-11-11-28 or DDR3-1333 9-9-9-24 if the kit does not have a standard profile for 800MHz.

[UberGeek]

I'm glad you pointed this out. I was always under the assumption that the memory controller was embedded on the motherboard. Of course, the QVL's I have don't identify this important fact which answers the question, how on earth did they manage to get (4) 8 GB 2400 modules to work in the first place.

Since I'm not married to this CPU and juggling memory options, it would be helpful to know about better CPU's for this particular board. This is my first AMD build and there's still lots to learn.

[emissary42]

Even though in terms of IMC quality it may help sometimes to just buy the higher/highest binned CPU parts, it is not primarily an issue of the actual CPU model, but variation from one sample to another. Someone might buy a single processor and can run 4x8GB @ DDR3-2400 no problems, while others buy 10+ pieces and in the end still are stuck at DDR3-1600/1866 with four modules.

To be fair this is not an issue limited to AMD either, as i had multiple i3 and i5 that crapped out pretty fast in terms of memory capabilities but most i7 at least are solid in that regard (you still have to bin them for serious benching, though).