Hello all, first time posting a question of my own here. I recently purchased a MSI 990FXA-GD80 V2 and I have a question about the RAM I purchased. The Newegg page says it supports up too 2133 OC speeds. I bought 2 sticks of 4g Corsair Vengeance 2133 RAM by mistake and my question is will the 2133 speed RAM I purchased be compatible with the motherboard or will I have to purchase new ones? I've tried searching around the internet for an answer and mostly I've seen that it will work but it will run at a lower speed (1600 with this motherboard i believe). If that is the case then if I would want to buy another set of Vengeance DIMs in the future should I buy the 1600 speed or the same 2133 as before.
Thanks for the clarification and whatever help you can give!
Well using high frequencies depends entirely on your CPU, so if you have and 'FX' then yes you can use higher frequencies, but if you don't then somewhere between DDR-1333 and DDR3-2000 can be used. Often high frequency kits i.e. DDR-2133 don't run 'very well' (bad CAS Timings and stability issues) when running at DDR3-1333 or less then their Rated Frequency & CAS -- they should but 'should' isn't 'will.'
Q - What CPU?
Q - What exact kit of RAM? ; please provide a link to your exact RAM.
Ideally, set the RAM manually: DRAM Frequency and CAS Timings, and run Memtest for 4-passes before installing the OS to aviod corruption. Memest create a bootable CD/DVD or USB Flash Drive, press (F8) to boot off the Memtest and let it run; link - http://www.memtest.org/#downiso
On a second thought of it all i managed to gather some extra change and i might be able to swing the 4X4GB kit. Am I correct saying that this would be an optimal choice for my system having 16GB of RAM?
Ideally, it's what I would do to avoid mixing-issues (i.e. failures). Now if you were looking at DDR3-1333~DDR3-1600 then the 'problems' are less of an issue depending upon the CAS Timings. Remember JEDEC's standard for DDR3-1600 is CAS 11 and for DDR3-1866 CAS 13.
So the question is, does saving $__ equate to no guarantees that they'll work together vs a guarantee that they will along with OEM full support. Question #1 if you have a problem is are you putting (2) two kits together and their immediate response will be try a lower frequency with higher CAS Timings and there's no guarantees with putting two kits together i.e. you're SOL.
My advise is and should be 'good' and for the 'best' possible results, it's a piece of cake for me to say anything you'd want to hear -- a lot less typing on my part.
Well, if you have 2 2x4's and they are different speeds, you can place them in opposing banks and they will operate together , just at the lowest speed of the two, I think maybe the timings or the CAS latency have to be the same... either that or they just will throttle to the slowest, I cannot recall. RAM is sold in sets because those sticks are specifically tested together, that is why it is usually advised to buy completely new sets instead of trying to mix and match, but it may work. You can give it a try, it shouldn't hurt. Also, the displayed speeds at OC are only obtainable by overclocking, if your MOBO lists a higher speed but does not postscript it with an (O.C), it may support an XMP profile at that speed (if your MOBO supports XMP that is..)
Don't ever mix IC's, nor Frequency/CAS/Voltages - you'll either have to use really slow Frequencies i.e. DDR3-1333 and or pray. Slowest wins. Also, XMP is an Intel only for of 'SPD' and doesn't pertain to AMD i.e. XMP doesn't work; you need to manually set the 'XMP' sort of settings e.g. (CAS-TRCD-TRP-TRAS-CR) BUT XMP is a lot deeper than those 5 common CAS Timing settings.
Next pray it won't be tossing-out errors like popcorn. So anything better than DDR3-1600 CAS 11 is a crap-shoot and the end result (if it works) is slower than either kit per it's Rated Frequency/CAS. Never on my rig.
What I posted above is unfortunately a common occurrence when, as you said "they are different speeds...or...no reason you cannot mix frequencies" so it's not advised.
The OP 'can' mix two of the same kits, but again read what I already said.
Most folks pay little attention to their RAM including mixing them together, and when they do and they have problems they come here or to other forums for help.
Listen, I'm putting (2) two identical 4x4GB kits together, and my BIOS is set using XMP (Intel) and tweaked on top of that (VCCSA, VTT, etc). There were no 8x4GB (32GB) DDR3L (1.35v) kits or that's what I'd be using. Also I'm not OC'ing (my RAM), my CPU (SB-E) is rated for DDR3-1600. I knew the risks...knock on wood so far so good.
Well, I always try to advise people that theoretically it should work, but that does not mean it will, as you did above. I do not see any reason why you would not at least try mixing RAM as such, especially if the frequency is the only difference. I understand timings are different story, but my understanding was that each bank of RAM is basically addressed separately and thus can be of different frequencies (this depends on the memory controller though as well I believe, not all will support it).