[SOLVED] Combining these two DDR3 kits - 9-9-9-24-2N (2x8) and 8-8-8-24-2N (2x4)

[dougtherug]

Hi,

I recently purchased these 2 sticks - https://www.gskill.com/en/product/f3-1600c9d-16gsr

Was wondering if it is worthwhile combining them with my old sticks - https://www.gskill.com/en/product/f3-12800cl8d-8gbxm

Have them all installed now and it seems to be running fine. Haven't done any stability testing or anything like that, though.

Will the old 2x4gb sticks slow down my new 2x8gb sticks? BIOS says theyre both running at 1600 now, but I'm not sure on the timings - I've found the options in my BIOS, but for some reason it displays different timings for both sticks which I didn't think was possible. My mobo is an Asrock extreme 4 990fx. I use my PC for music production and occasional gaming.

Any advice is appreciated. Thanks.

 

[Deleted member 217926]

The old cas 8 sticks will likely default to the slightly slower cas 9 of the new sticks. As this is an AMD system I'd run memtest overnight to be sure it's stable. If there are no errors you should be good to go.

 

[prince_xaine]

Your old memory will absolutely slow down your new memory. Is there any chance you can run off of the new memory only? AMD likes fast memory, so it'd likely increase your performance more in the long run. If you keep both pairs, just refer to the above post.

 

[dougtherug]

For some reason my old sticks seem to appear as CAS11 in my BIOS when running at 1600. Is it possible the advertised CAS is only at 1333?

16gb is plenty, thought I may as well use the old ones rather than sell them for a small price. If they're going to decrease the performance of the new ones, then I won't.

Thanks for your responses.

 

[Deleted member 217926]

Your old memory will absolutely slow down your new memory. Is there any chance you can run off of the new memory only? AMD likes fast memory, so it'd likely increase your performance more in the long run. If you keep both pairs, just refer to the above post.

Ryzen likes fast memory. OP has an FX8320.

The difference between cas 8 or cas 9 is tiny. Certainly nothing noticeable. Also how is the old cas 8 memory going to slow down the newer cas 9 memory when the old RAM is faster cas 8??? There's not a correct statement in that post.

FX can have problems with all 4 DIMMs populated and FX doesn't like mixing memory though. Try it. If it's stable with an overnight run of memtest you're good. If not it may be possible to tweak some settings and get it stable.

 

[prince_xaine]

The general rule of thumb is to not mix the modules. Not that following this is a must.

I also misread the original sites and thought the new sniper modules had the lower latency - my apologies.

Enable XMP profile or manually adjust the timings so they match.

 

[dougtherug]

Thanks guys. Decided to just go with the new ones, not worth any sort of risk when I don't need the extra ram.