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Is 4000MHz CL18 ram slower than 2666 CL16 ram on a cpu limited to 2666?

Tumleren
Go to solution Solved by Hairless Monkey Boy,
1 minute ago, RONOTHAN## said:

Yeah, basically. Unless you're on a B460 motherboard, you can probably overclock your memory no matter the CPU.

locked 10th gen CPUs still have a memory speed cap on B560. OP is on Z370, though. I don't know of any artificial cap with i5-8600 and Z370.

 

5 minutes ago, Tumleren said:

This is the page for my motherboard, this is for my CPU. Are you saying I would be able to run the RAM at more than the 2666 listed on the CPU spec sheet?

My recommendation would also be to go for DDR4-3200 CL16. It's one of the more common and therefore cheaper options available, and will provide plenty of performance for your CPU.

So I'm looking at getting more RAM, and am confused about how it will work with my CPU.

 

Currently I have 2 sticks 2666 CL16 ram on an i5-8600 that, according to Intel's spec sheet on ark, supports up to 2666.

 

If I upgrade to a kit of 2x 4000 CL18, for example, will it be slower since it will downclock to 2666 with CL18 timings? I won't be getting the benefit of the 4000 mhz frequency, right?

 

I'm upgrading mainly for capacity, but figure that some sort of "future-proofing" might as well be done by buying something higher frequency.

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It depends on the profiles stored in the ram stick.

The stick will probably have 2666, 2933/3000 , 3200, 3600 and probably 3800 something profiles. The 2666 and under profiles will probably have crappy JEDEC timings set and default voltage of 1.2v but you can use the timings from 3000 or higher with 2666 mhz preset and manually set the timings.

 

If the stick can do 4000 mhz with cl18, it can probably do 3600 mhz with cl16 or cl17, it can probably do 3200 mhz at cl15 and 2666 mhz at even lower latency.

But, that 4000 Mhz is probably achievable with 1.45v or something higher than 1.35v - if you take the voltage down to 1.35v which is safer for older cpus, then the latency may not go as low, but cl 16 should still be doable.

 

I personally wouldn't spend money on ram higher than 3600 mhz whatever the latency. Don't buy with future proofing - we're down to last cpus that use DDR4 - next Intel and AMD processors will use DDR5.

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You're correct. CL18 is slower then CL16. Since you're capped at 2666mhz, you'll only be gaining RAM capacity and increasing latency.

Salisbury steak isn't steak.

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2 minutes ago, Darkwing Drex said:

You're correct. CL18 is slower then CL16. Since you're capped at 2666mhz, you'll only be gaining RAM capacity and increasing latency.

Except effective speed doesn't work like that. CL16 3200MHz and 3600MHz CL18 are effectively the same speed, and since this kit could run at 4000MHz CL18, it would probably be able to run at something like 2666MHz CL12, way faster than CL16. Also, depending on the motherboard this guy is running, he's probably not capped at 2666MHz, and would be able to run at a higher speeds like 3200MHz. 

 

19 minutes ago, Tumleren said:

I'm upgrading mainly for capacity, but figure that some sort of "future-proofing" might as well be done by buying something higher frequency.

I wouldn't bother trying to "future-proof" memory, since DDR5 is around the corner, and by the time you wanna upgrade your CPU platform, you'll want to get on something DDR5. If you really only care about capacity, get the cheapest kit you can find with the capacity you want. If you want a little extra performance, you can get something rated at 3200MHz CL16, which would only be a small amount extra and give you a decent bump in performance. 

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12 minutes ago, RONOTHAN## said:

 Also, depending on the motherboard this guy is running, he's probably not capped at 2666MHz, and would be able to run at a higher speeds like 3200MHz.

This is the page for my motherboard, this is for my CPU. Are you saying I would be able to run the RAM at more than the 2666 listed on the CPU spec sheet?

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1 minute ago, RONOTHAN## said:

Yeah, basically. Unless you're on a B460 motherboard, you can probably overclock your memory no matter the CPU.

locked 10th gen CPUs still have a memory speed cap on B560. OP is on Z370, though. I don't know of any artificial cap with i5-8600 and Z370.

 

5 minutes ago, Tumleren said:

This is the page for my motherboard, this is for my CPU. Are you saying I would be able to run the RAM at more than the 2666 listed on the CPU spec sheet?

My recommendation would also be to go for DDR4-3200 CL16. It's one of the more common and therefore cheaper options available, and will provide plenty of performance for your CPU.

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Alright, depending on the price I'm going to go for some 32 or 3600 MHz cl16 and see if I can run it at that. Thanks guys, much appreciated 

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5 minutes ago, HairlessMonkeyBoy said:

OP is on Z370, though. I don't know of any artificial cap with i5-8600 and Z370.

From what I've seen online, there isn't. I was mainly stating B460 since it's one of the big ones that is locked. 

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