Memory Advice (x570)

[cobhc]

Hi all,

 

Looking at putting together a build with a 3950x and a Asus Crosshair VIII Hero and struggling with memory choice.

 

Thisis going to be an Unraid build (upgrading current server) and I'd like 64gb, but don't want to leave too much on the table gaming performance wise. We seem to get raped over here in the UK with prices on anything but Corsair, I see G Skill going for much cheaper in the US/Canada.

 

Would 3600C17 really be that much of a downgrade compared to 3600C16 or 3200C14 as a 32gb kit of 3600C17 is around £200 where as the others are over £300 generally?

 

[Jurrunio]

1 minute ago, cobhc said:

We seem to get raped over here in the UK with prices on anything but Corsair, I see G Skill going for much cheaper in the US/Canada.

there is uk.pcpartpicker so no problem

 

2 minutes ago, cobhc said:

Would 3600C17 really be that much of a downgrade compared to 3600C16 or 3200C14 as a 32gb kit of 3600C17 is around £200 where as the others are over £300 generally?

in max potential or just at rated settings?

[Stu_Bear]

3600c17 is fine...I'd not worry about it.  I'm running CAS 17 ram on my home pc...scores in the 99th percentile in all areas.

[nick name]

Sounds like the expensive kits are Samsung b-die.  The difference between the kits I think is gonna be about a handful of frames so it's not something you'll notice unless you measure it.  So unless you like measuring and competitive benchmarking -- I don't think you're gonna be too upset with the cheaper kits.  

[ddennis002]

34 minutes ago, Stu_Bear said:

3600c17 is fine...I'd not worry about it.  I'm running CAS 17 ram on my home pc...scores in the 99th percentile in all areas.

Running a odd number CAS on ryzen isn't a good idea, by default this turns off gear down mode and can cause stability issues. 

[cobhc]

Edit: Post made in error.

 

[Stu_Bear]

5 minutes ago, ddennis002 said:

Running a odd number CAS on ryzen isn't a good idea, by default this turns off gear down mode and can cause stability issues. 

That's news to me...glad you responded.

[Guest]

Read and write plus memory latency comes from raw speeds, but timings have a direct effect on latency.

 

Fast with tight as possible timings is desired.

 

 

[cobhc]

49 minutes ago, Jurrunio said:

there is uk.pcpartpicker so no problem

 

in max potential or just at rated settings?

At rated settings, looking for stability really.

43 minutes ago, Stu_Bear said:

3600c17 is fine...I'd not worry about it.  I'm running CAS 17 ram on my home pc...scores in the 99th percentile in all areas.

Ah nice, thanks for the feedback.

10 minutes ago, nick name said:

Sounds like the expensive kits are Samsung b-die.  The difference between the kits I think is gonna be about a handful of frames so it's not something you'll notice unless you measure it.  So unless you like measuring and competitive benchmarking -- I don't think you're gonna be too upset with the cheaper kits.  

Hopefully I'll be okay then.

6 minutes ago, ddennis002 said:

Running a odd number CAS on ryzen isn't a good idea, by default this turns off gear down mode and can cause stability issues. 

I had seen something relating to that. Seems like a minefield with Ryzen.

[nick name]

7 minutes ago, ddennis002 said:

Running a odd number CAS on ryzen isn't a good idea, by default this turns off gear down mode and can cause stability issues. 

This isn't always the case.  It's an issue with weaker kits or larger capacity kits so it covers many of the kits out there, but something like a 16GB 3600CL15 Samsung b-die kit will run its 15-15-15-15 XMP/DOCP profile with Geardown enabled.  

[ddennis002]

1 minute ago, Stu_Bear said:

That's news to me...glad you responded.

Third gen ryzen with its memory improvements may have changed these facts as I haven't upgraded from 2700x yet plan on a 3950x when taxes show up.

Its not that you cannot do it but every system I have helped OC ram running CAS at a odd number almost never results in a Stable OC. Due to gear down gets disabled.

Generally lower bined kits you will run into this issue.

 

[ddennis002]

7 minutes ago, nick name said:

This isn't always the case.  It's an issue with weaker kits or larger capacity kits so it covers many of the kits out there, but something like a 16GB 3600CL15 Samsung b-die kit will run its 15-15-15-15 XMP/DOCP profile with Geardown enabled.  

You can NOT run odd timings with geardown enabled. XMP is a Intel spec the only reason AMD motherboards can run it is because the manufactures have the profiles and bake them into AMD boards. So yes you can run a 15-15-15-15 XMP profile but geardown will be disabled on ryzen. It will automatically force timings to even numbers if you enable geardown on a odd CAS kit. Intel can run odd number of timings anytime because intel cpus don't support gear down mode.

[cobhc]

Just to clarify, I won't be overclocking at all and ideally want 64gb, although will probably buy 32gb to start off.

[boggy77]

2 minutes ago, cobhc said:

Just to clarify, I won't be overclocking at all and ideally want 64gb, although will probably buy 32gb to start off.

you need to enable xmp or docp in bios anyway to get ram to run at the advertised speed. otherwise it will be 2133 or 2400 regardless of what kit you buy

[Jurrunio]

1 hour ago, cobhc said:

and I'd like 64gb, but don't want to leave too much on the table gaming performance wise.

Isnt Corsair selling 64GB 3000MHz/3200MHz CL16 kit for about 260 pounds? I'd rather get that. You wont lose that much performance and you could compensate some of it by just raising the FCLK

[Stu_Bear]

How high can you crank FCLK on an AMD mobo/chip?  Intel cuts you off at 102.9

[cobhc]

27 minutes ago, Jurrunio said:

Isnt Corsair selling 64GB 3000MHz/3200MHz CL16 kit for about 260 pounds? I'd rather get that. You wont lose that much performance and you could compensate some of it by just raising the FCLK

Yeah, about £270-£280. It seems like a good deal I just didn't want to be losing too much. I might be overthinking it.

 

29 minutes ago, boggy77 said:

you need to enable xmp or docp in bios anyway to get ram to run at the advertised speed. otherwise it will be 2133 or 2400 regardless of what kit you buy

Yeah, I'm aware of that but I wouldn't want to bother tweaking past doing that.

[nick name]

40 minutes ago, ddennis002 said:

You can NOT run odd timings with geardown enabled. XMP is a Intel spec the only reason AMD motherboards can run it is because the manufactures have the profiles and bake them into AMD boards. So yes you can run a 15-15-15-15 XMP profile but geardown will be disabled on ryzen. It will automatically force timings to even numbers if you enable geardown on a odd CAS kit. Intel can run odd number of timings anytime because intel cpus don't support gear down mode.

Crap.  I misremembered having done it with my kit.  It would have been a while ago so I probably am misremembering being able to do it as I can't reproduce it now.  That means I've been spreading damn dirty lies.  That's my bad.  

[Jurrunio]

3 hours ago, Stu_Bear said:

How high can you crank FCLK on an AMD mobo/chip?  Intel cuts you off at 102.9

You're talking BCLK in that case, not FCLK. Ryzen corrupts NVMe SSDs with BCLK over 101MHz so it's really not worth doing.

[cobhc]

So going for a 64gb set of 3200CL16 won't leave too much on the table performance wise and I'll have less chance of stability issues?

[ddennis002]

35 minutes ago, cobhc said:

So going for a 64gb set of 3200CL16 won't leave too much on the table performance wise and I'll have less chance of stability issues?

If you going to go with a 3200 kit i could go with a CL14 kit or a 3600 kit CL16.

[cobhc]

3 minutes ago, ddennis002 said:

If you going to go with a 3200 kit i could go with a CL14 kit or a 3600 kit CL16.

I would, but they're 2.5-3 times the price in the UK...hence this topic.