Pretty much just what is says in the title. I just bought myself an RX 6600 and I thought I’d try to get the most out of it by replacing my old Ryzen 7 1700X with a new 5600 since that is still compatible with my mainboard (I haven’t bought it yet). Ryzen 1000 really liked faster memory so I bought 16GB of GSkill Ripjaws V 3200MHz back in the day. I’d assume that still holds true for Ryzen 5000 but to what degree?
Will my 3200MHz memory still be good enough or do I have to shell out cash for 3600+MHz RAM now? (which is something I really don’t want to do. I didn’t even plan on getting a new CPU, this was just supposed to be a GPU upgrade)
That should be fine, I use some Corsair 3200 with my 5800x
2 Likes
The Ryzen 5600 spec says up to 3200MHz. So, from that front you’re good.
Many people buying new systems go for DDR4-3600 memory as that is the most beneficial overclock for this generation of CPUs.
I don’t think you would notice the difference in day-to-day or gaming activities.
4 Likes
Ah perfect, thank you
What exactly do you mean by this? If it’s up to 3200MHz, how would 3600 be more beneficial?
in addition to the increased memory bandwidth, infinity fabric and memory controller speed is tied to ram speed, infinity fabric is the interconnect between CCXs (different parts of the cores) CCDs (not important for 5600 as it only has one) and communications between the CCDs and the IO die, since they’re separated any latency and bandwith bottlenecks are exaggerated even more
basically 3600 is the sweetspot as most chips will hit it where 3200 is guaranteed
3 Likes
@GigaBusterEXE provides the technically correct info.
In normal speak: at DDR4-3600 all the internal memory performance related stars align for that platform 
in real terms you wont be able to tell any difference.
run the 3200 at cas 14 and you get all but the same performance as 3600 cas 16. all be it with a little less bandwidth.
if you already have 3200 ram then i wouldn’t consider it a good value upgrade to jump to 3600.
yes its the sweet spot.
but that 3200 will get you 97% of the way there at zero extra cost.
3 Likes
I thought it was 1800-1900MT/s x 2? I could be wrong but IIRC 3800Mhz is the optimized sweet spot? But I think you have to change stuff in the BIOS. Besides, the difference between 3600 and 3800 may not be significant enough to warrant the headache of manually fine tuning RAM (hence I leave mine at the default XMP preset 
)
It will depend on the programs being run, but that 3200mhz kit should be fine. The benefits are noticeable only in CPU starved scenarios, and with that 6600 you are more likely to be GPU bound in games.
3200mhz is the officially supported top speed, so the “sweet spot” is that and anything else is a bonus.
1 Like
once you go over 3733 the ram is forced into 2T mode. and will switch to 1 dim per channel.
so 1866 is the limit of the infinity fabric on ryzen 5000
but 3733 is an odd timing which means it cant reach the lower cas latencies that 3600 can.
end result the 3600 is effectively faster than 3733 once you take into account cas latency as well as bandwidth of (MT/s).
3 Likes
Great summary. I want to add that a lot of Ryzen 5000-series chips seem to have a “hole” at 1900MHz FCLK, meaning they can sometimes post at e.g. 1866 and 1933 but not 1900. Also, you can start getting IF errors above 1866 that are silently corrected, i.e. they don’t result in a crash and the only way to detect them is to look for a roll-off in benchmarks that correlate strongly with IF performance. All that is to reiterate: 1800MHz 1:1:1 is best on Zen 2 and 3 and it’s really not worth chasing anything higher.
2 Likes
3200 is perfect. Realistically the memory controller in the 5600X can’t handle much more than that for daily use, and you won’t notice much difference anyways. Besides, you can always try manually overclocking your RAM, rather than paying somebody else to do it. FYI 3200 MHz is the fastest speed DDR4 chips can get from the factory. XMP is just a factory overclock saved in the RAM’s onboard non-volatile memory chip. It’s a not even a full overclock. So buy some RAM which is made with 3200 MHz chips from the factory, and overclock it yourself.
2 Likes
XMP is still something that slightly confuses me. If I understand correctly, my RAM usually runs at 2133 but XMP OCs it to 3200 (which is why it is advertised as). I recently noticed that some software still reports the RAM as 2133MHz even with XMP enabled (although Windows recognizes it as 3200MHz). Is this normal behavior with XMP or should I be worried?
1 Like
Probably reading the SPD values, which are often 2133mhz. What software are you using? If on Windows, things like HWInfo and CPU-Z will give you both SPD and XMP values.
That would be the SPD value of your RAM. Basically, it’s the factory default speed of the chips. Some are SPD 3200, now. They can usually OC higher, but may cost more. XMP is just a factory OC that is stored in the RAM to make it easier to OC. It’s not a complete OC, though. Also, it’s a way for RAM makers to charge people more money for the same RAM. Everything that profile does can be done manually.
2 Likes
A R5-5600 will also likely be much less sensitive to memory than an old 1700x because:
- we now have 8 core CCXs, so all cores on your R5 are on a single CCX on a single die (with 2 disabled cores) - unlike your 1700x which had 4 cores in each of 2x CCX units
- this means no cross-CCX chatter between cores in different CCX units across infinity fabric, which is tied to DDR4 speed
- Ryzen 5000 has bigger, faster CPU caches as well
So, a number of issues with Zen1/Zen+ responsiveness being tied to infinity fabric (and thus, DDR) speed are no longer a thing for the R5 and R7 5000 series. It’s only on the multi-die R9 chips that you now run into infinity fabric between cores. Yeah you still go over fabric to memory on R5/R7, but the inter-CCX traffic is eliminated.
I’d keep the memory you have and not worry about it. Diminishing returns, and an RX6600 won’t be pushing the CPU anyway.
Save the money for something else
3 Likes
I think I was using some kind of benchmark. I just home today, so I’ll give HWinfo a go later
Thank you, that’s a relief!
