RAM, 3200mhz cl16 vs 3600mhz cl18?

[JimmyHackers]

i have an 8700k (delid 5ghz oc custom water cooled), tuf z390 plus gaming mobo, 1080ti, and currently 16gb (2x8gb) of crucial 2400mhz cl16 ram.

 

the difference between the two kits (described in thread title) at my local pc shop is 2 quid. 40 and 42 pounds respectively.

 

so......my question is..... which should i go for?

 

pc use is mainly gaming, fallouts, mechwarriors, kerbal,

[Eigenvektor]

3600 MT/s is faster.

CL18 @ 3600 MT/s translates to the same absolute latency as CL16 @ 3200 MT/s.

So overall the 3600 MT/s should be better

[RONOTHAN##]

6 minutes ago, JimmyHackers said:

currently 16gb (2x8gb) of crucial 2400mhz cl16 ram.

Odds are you can just overclock this to 3200 CL16 very easily by just bumping the voltage to 1.35V, so unless you're going for a higher capacity kit that's what I'd do first. Just raise the voltage, set the frequency to 3200, and the timings to 16-18-18-38 and you should be good to go. 

 

If that doesn't work, get the 3600 rated kit. Theoretical latency should be basically the same, but the memory controller is clocked higher so the 3600 kit should get a slight theoretical latency advantage as well as a bandwidth advantage since it's clocked higher. The 8700K has a good enough memory controller that 3600 is pretty reliable to work. 

[hirushaadi]

just get the 3600mhz cl16, if your main purpose is gaming, the 3600MHz at a cas latency of 18 (cl16) might actually perform better

[hirushaadi]

4 minutes ago, Eigenvektor said:

CL18 @ 3600 MT/s translates to the same absolute latency as CL16 @ 3200 MT/s.

is there a way to calculate it or estimate it?

 

[Eigenvektor]

Just now, hirushaadi said:

is there a way to calculate it or estimate it?

Yes, there is.

 

The shortened formula is CL * 2000 / Frequency. This gives you absolute latency in nanoseconds.

 

18 * 2000 / 3600 = 10

16 * 2000 / 3200 = 10

[toasty99]

Seems kind of odd you'd want to replace your current ram. Just overclock it, use it till you finally do a whole new build.

[RONOTHAN##]

1 minute ago, hirushaadi said:

is there a way to calculate it or estimate it?

 

The theoretical calculation for 1st word latency is CAS latency * 1000 * 2 / data rate. Practically speaking with how timings actually work out, on DDR4 it should be (tCL + tRCD + 4) * 1000 * 2 / data rate, and there are many more factors that play into latency than just those theoretical calculations that also need to be considered (on Ryzen, for instance, 3800 CL16-16-16 will get you lower latency than 3600 CL14-15-15 because the infinity fabric is clocked a lot higher, even though by both of those calculations the 3600 CL14 setup should have better latency). 

[JimmyHackers]

well, i had my first go at overclocking ram, twas susccessful (few hiccups)

 

im now succesfully running 1.35v 16 18 18 38 3200mhz (bumped my cinbench a whole 100 points)

 

thank you very much for suggesting to oc the ram, i dont need to spend any money now .

 

questions: I tried 1.35v 16 18 18 39 (accidentlay didnt set the 38 right) 3200mhz and i got a few bsod using cinebench.

                    then 1.35v 16 18 18 39 (Still hadnt seen my mistake) 3000mhz and it ran fine

                    finally, i discovered my mistake and now no crashes in cinbench at 3200mhz

whats up with that?

can i push it any further? 

 

thanks again

jim               

[JimmyHackers]

meh :s spoke to soon

 

fallout 76 crashed at 3200mhz, didnt at 3000mhz, still a nice performance bump though.

[Somerandomtechyboi]

1 hour ago, JimmyHackers said:

crucial 2400mhz cl16 ram.

Could you take a pic of the black squares (ram ics)?

 

If its rev e then 4500+ is doable

If rev b then maybe youll cap out somewhere around 3800

[JimmyHackers]

they are crucial ballistix sport....the red heat spreaders obscure the ics

 

i took a pic of the stickers though....not sure how much help they will be.

[RONOTHAN##]

4 hours ago, JimmyHackers said:

they are crucial ballistix sport....the red heat spreaders obscure the ics

 

i took a pic of the stickers though....not sure how much help they will be.

It's rev. B. Odds are if you tried you could get 3600 CL16-19-19-39 to work without too much difficulty, though odds are you'd have to bump the voltage up slightly to 1.4V rather than 1.35. 

 

I will want to point out that Cinebench is the least memory intensive benchmark out there, and you still want to do a full memory stress test to make sure it's actually stable, especially since you were getting BSODs with tRAS one tick higher. No idea why it did that BTW. 

[JimmyHackers]

lol, much difficulty encountered. (honestly thought id bricked something)

 

tried the above 1.4v 3600mhz 16 19 19 39 and got a black screen, constant reboot loop with no screen output.

 

learnt where my bios reset jumper was (wish it was a button), didnt seem to help, still kept boot looping with no screen output.

 

i unplugged the main monitor, put it into the mobo display port, got the bios screen on secondary monitor still in gfx card. missed the f2 prompt :S,

 

next restart it loaded the bois prompt on the main monitor through the mobo output, i checked bios had been reset (it had)

 

turn off pc, put main display cable back in gfx card.........starts up normal as anything..... i did a restart and put my bios back to "my normal" and the newish 3000mhz setting for the ram.

 

things back to normal, but damn what a faff. i think 3000mhz is the limit for this ram.

 

[Ebony Falcon]

5 hours ago, JimmyHackers said:

lol, much difficulty encountered. (honestly thought id bricked something)

 

tried the above 1.4v 3600mhz 16 19 19 39 and got a black screen, constant reboot loop with no screen output.

 

learnt where my bios reset jumper was (wish it was a button), didnt seem to help, still kept boot looping with no screen output.

 

i unplugged the main monitor, put it into the mobo display port, got the bios screen on secondary monitor still in gfx card. missed the f2 prompt :S,

 

next restart it loaded the bois prompt on the main monitor through the mobo output, i checked bios had been reset (it had)

 

turn off pc, put main display cable back in gfx card.........starts up normal as anything..... i did a restart and put my bios back to "my normal" and the newish 3000mhz setting for the ram.

 

things back to normal, but damn what a faff. i think 3000mhz is the limit for this ram.

 

I went through same thing with my ram oc, had to power down and clear cmos

thought I had bricked something too but was all good. There’s a decent ram kit that was recommended to me by Ron, the fury renagade 3600 cl16 32gb kit that’s also dual rank 

 

you could also try 1.4 18-20-20-40 

If that don’t boot drop clocks to 3200