Any problems mixing "old" and new RAM kits (identical models)?

[rseiler]

I have a late-2011-era G.Skill F3-12800CL9D-8GBXL kit (2x4GB) that's been in use since then. Recently, I bought the same kit to get to 16GB, with the only apparent difference being that it's manufactured in April 2015.

Is there likely to be a problem because of this age difference?

 

[dave_the_nerd]

Nah. Not at stock speeds, anyway.

 

[mikeymikec]

I have 2 DDR3-1600 kits installed, one is 5 years older than the other. No problems.

 

[rseiler]

Great to hear. I won't be playing with the speeds at all except maybe manually setting it to what XMP (probably no longer available with two sets) normally provides (the rated speed of 9-9-9-24 with it; 11-11-11-28 without out it), but that's not a big deal either way as long as it's stable.

 

[rseiler]

I have 2 DDR3-1600 kits installed, one is 5 years older than the other. No problems.

One difference I noticed with the new set is that it's not double-sided, though it's hard to see that with the heat spreaders. Diags call them "1 rank, 8 banks" vs the "2 ranks, 8 banks" of the old set.

Also, the "automatic" tRFC is 208 with just the new set and 128 with just the old set.

When both sets are in the system (I have the new set in Channel A, though not for any particular reason), the system does boot and function, but only on "automatic," which means 11-11-11-28. With either set alone, I'm able to set it to the rated 9-9-9-24. Not a big deal, I think.

Update: It will boot and work with CL9 when you take CR off Auto and manually set it to 2. Auto had been setting it on 1 with 8GB, but it needs to be on 2 with 16GB.

 

[harobikes333]

Nah. Not at stock speeds, anyway.

This. I recently added some RAM to a setup that was 8 years apart. Worked like a charm.

 

[Cerb]

Try it. I ran kits of different ages for years in my Core 2. When trying to use it for an upgrade on another PC, one stick from each kit wouldn't work, even though they were the same exact SKU, with the same specs, but a matched set worked fine. Usually, it works.

 

[sandorski]

There possibly could be an issue, but probably not. Especially at Stock speeds.

 

[BonzaiDuck]

Never tried it with other brands, but I actually mixed a kit of G.SKILL "Black Pi" DDR2-900's with a G.SKILL "PQ" set of DDR2-1000's. Of course, there was an overlap in the JEDEC data across the two kits for both latencies and voltage. This is not something I would recommend, even though the combination was rock-stable for as long as it was needed -- about five years.

If the manufacturer produces the same model (for instance, "-GBRL" or "-GBXL") with some slight difference in the design such as noted by the OP, there should be little doubt that they will work together.

On the observation concerning auto-configured command-rate, rseller's observations are no doubt accurate. I also had noticed that my motherboard would choose CR=1 on "Auto." But the memory spec as shown -- even in the mobo's XMP "Profile" -- was CR=2.

Without offering a guarantee, I'd suggest that the OP try upping the voltage for the IMC (if the processor is Intel). On chipsets and CPUs familiar to me, it was safe to set VCCIO as high as 1.2V, but you only needed to increase it from ~ 1.0 to around 1.13V to make the kits function with CR=1.

 

[mikeymikec]

One difference I noticed with the new set is that it's not double-sided

The last time I encountered an issue with mixing single and dual-sided RAM was about ten years ago with DDR1, so I honestly wouldn't be worried about noticing if modules were one or the other.

Through my work I've done an awful lot of module mixing, brands, speeds, whatever. Admittedly I stick to Kingston/Crucial because in my experience they're the most compatible modules, but I can't remember the last time I encountered a compatibility issue.

One factor I can think of that may help categorise my experiences though is that I don't often play with more expensive modules with unusual timings. The modules I'm using in my own system are CL9 DDR3-1600s (all four of them) though.

 

[hawtdawg]

I bought 2 8 gig ripjaws sets 2 years apart and was able to maintain my overclock/timings. You just need to make sure you get the same model number.

 

[darkfalz]

Sometimes they change timings on revisions, especially if the actual chips come from a third party. But out of the two sets usually the most relaxed timings will be used and it should work most of the time.

 

[Valantar]

As long as the voltages and timings match up, there should be no problem. I did the same years ago with my old DDR2 desktop, from 2x2GB to 4x2GB. The same kit, but the new one had slightly worse timings. After adjusting the old kit so that they matched, it's been completely stable for years.