3600mhz vs 3200mhz RAM

[dani72]

I recently ordered a PC which included 64GB 3200mhz RAM. I asked PCS about changing it to 3600mhz RAM instead because it's not an option in the configurator. I also asked them why it wasn't an option and they came back with this:

The reason for this is it can cause instability issues.

If you wish to have this we can look into it for you but PCSpecialist cannot help with instability issues caused by the RAM in the future.

Is it worth risking the "instability issues" that might occur? Would it be better to switch to 32gb of the faster RAM?

 

[NoddyPirate]

I can see your ordered spec on your other posts - but you might repost them here for completeness if that's OK.

A few things I'd say on this:

In general the majority of issues with 3600 MHz RAM seem to occur with 4 sticks. Officially Ryzen supports up to 3200 MHz with more than that not necessarily guaranteed and largely dependent on the Motherboard. The difficulty a Motherboard can have with pushing the RAM speed higher than 3200 MHz in accordance with the SPD info on the RAM itself increases with 4 sticks or more.

Latency is the key factor in your decision really. PCS seem to supply 3200 MHz at CL16 - and 3600 MHz at CL18. The real latency between these two is exactly the same - (CL / MHz) * 2000 - however you will still have a higher FCLK (or Infinity Fabric Clock) with the faster RAM as it must be synched 1:1 with the Mem Clock. Much guidance suggests that even with the same real latency, the higher speed RAM will still see slightly better performance, along with the higher FCLK which will help with a two die CPU like the 5900X. But I don't think it would be an earth shattering difference by any stretch.

If you have decided that 64GB is what you needed in the first place, I can't see any way that you will be better off with 32GB of faster RAM, unless you have totally overspecced your RAM for no specific reason. But as you might see from the above, the performance difference you would likely see would probably be much closer to marginal that terrific.

Having said all that - it really does depend on your workload and usage so do your research and try to figure out what difference it will really make. You could try the 3600 MHz RAM and if you suffer instability just reduce the speed until it remains stable - as others have done here - or you may be better off sticking with your 3200 MHz RAM and seeing if you can improve the timings and/or Overclock the speed yourself later if you were so inclined - although obviously this would be done at your own risk.

(EDIT - updated)

 

[NoddyPirate]

Juts thinking about this a little more:

The other thing that I believe could make a notable difference is whether the RAM sticks are single or dual rank. My 16GB 3000 MHz sticks are single rank, but I have no idea what the layout is for 3200 MHz or 3600 MHz Corsair RAM.

Is there anyone else here that has a 16GB DIMM in either of those two speeds that could tel us? Of @dani72 if you are putting a question to PCS it would be worth asking that question too maybe - what is the CL of their 3200 vs 3600 RAM and what is the rank layout of each - single or dual.....

 

[Scott]

You're into a can of worms with the Single Vs Dual rank. It's like a rabbit hole of if's & but's

3200mhz & 3600mhz from PCS are so close you would struggle to measure it. At the same capacity the ranking would be the same so I don't think there's much to be concerned over.

There is variation of course, but one system will vary to the next also with stability & even non-crash stability (memory errors).

The 3200 C16 & 3600 C18, as far as I'm aware, is binned right next to each other. I don't think you would struggle to clock 3200 C16 up to 3600 C18 if you chose. If you wanted to take a punt though.... the 3600 offers the simplest versatility. If it doesn't work at 3600 C18 simply drop it down to 3200 C16 and you're where you started anyway.... only with a slightly better bin.

 

[NoddyPirate]

You're into a can of worms with the Single Vs Dual rank. It's like a rabbit hole of if's & but's

I've been reading up a lot on it and for the most part my face has looked like and the entire time!

It seems that four single rank DIMMs would be better than four dual rank DIMMs - but as you say I can't really see that sticks with identical capacity would be configured differently just because of their speed.

But at the same time I've read that the majority of 16GB sticks would be dual rank - which my 3000 MHz aren't - so who knows!

I'm with you on the 3600 MHz punt though - you make a good case sir @Scott !

 

[Scott]

I've been reading up a lot on it and for the most part my face has looked like and the entire time!

It seems that four single rank DIMMs would be better than four dual rank DIMMs - but as you say I can't really see that sticks with identical capacity would be configured differently just because of their speed.

But at the same time I've read that the majority of 16GB sticks would be dual rank - which my 3000 MHz aren't - so who knows!

I'm with you on the 3600 MHz punt though - you make a good case sir @Scott !

What's the model number of the RAM? Must admit, that's quite surprising. Most 16GB modules are dual as they save the denser chips for the 128GB packages (and above).

 

[NoddyPirate]

What's the model number of the RAM? Must admit, that's quite surprising. Most 16GB modules are dual as they save the denser chips for the 128GB packages (and above).

CM4X16GD3000C16K4D

Yes, I was surprised too - it shows as single rank in HWInfo and CPU-Z - it could be reported incorrectly perhaps....?

 

[NoddyPirate]

I'll try to see if I can spot the label on the sticks later maybe - they may have the 1R or 2R designation on them.....

 

[Scott]

I can't see why either would get that wrong to be honest. It does tend to happen as the yield rates mature. You get denser chip availability, it'll be cheaper than dual rank as time goes on.

Have you not enabled the 3000Mhz RAM profile? Or was that while tweaking?

 

[NoddyPirate]

I can't see why either would get that wrong to be honest. It does tend to happen as the yield rates mature. You get denser chip availability, it'll be cheaper than dual rank as time goes on.

Have you not enabled the 3000Mhz RAM profile? Or was that while tweaking?

No DOCP - I’m manually overclocked to 3200 MHz.

Just to add - RAM shows as 3200 in Task Manager and obviously the performance hike is visible in benchmarks too. But it always shows as 1066 within the above two. Not entirely sure why. The DIMMs are 2133 stock.

I’m assuming that it’s simply the board doing the OverClocking directly and the RAM just reports it’s stock speed?

 

[Scott]

No DOCP - I’m manually overclocked to 3200 MHz.

Just to add - RAM shows as 3200 in Task Manager and obviously the performance hike is visible in benchmarks too. But it always shows as 1066 within the above two. Not entirely sure why. The DIMMs are 2133 stock.

I’m assuming that it’s simply the board doing the OverClocking directly and the RAM just reports it’s stock speed?

I was pretty sure you would have done.

Not sure why it's reporting like that.

In CPUz does the Memory tab show your current frequency?

 

[NoddyPirate]

I was pretty sure you would have done.

Not sure why it's reporting like that.

In CPUz does the Memory tab show your current frequency?

Oooh - can’t remember! Away from the PC now for a few hours - about to get stabbed with a scalpel - so I’ll check that later too!

 

[NoddyPirate]

In CPUz does the Memory tab show your current frequency?

So it does!