Can CPU memory controller bottleneck RAM?

[say_wat_now]

The 6700k memory controller supports DDR3L-1333, DDR3L-1600, DDR4-1866, and DDR4-2133 memory.

 

So say I put in a 2400MHz stick of RAM with a 6700k processor. Will it be bottlenecked down to 2133MHz? And if it is I can overclock it to support 2400MHz?

 

If I overclock my RAM through the UEFI am I modifying the memory controller support or am I modifying the speed of the actual RAM stick?

 

i confuse, pls halp thnx

[Energycore]

If you're using a Z170 chipset motherboard, you can set RAM to run at higher than 2133MHz through manual overclocking or through the XMP option in the BIOS.

 

The important bit is that it'll be fine

[SydneySideSteveSomewheres]

The bottleneck you may have seen referred to has to do with timings and MHz range of the RAM itself.

For example, if you were to install both the 2400MHz RAM stick and the 2133MHz RAM stick (DDR4 obviously) and both of the RAM sticks had a MHz range they could share then they would work. However, if they were able to work together they would be operating at the lowest common MHz range regardless of how much you tried to overclock.

See the post made earlier -from over here- where there is a picture (as below)

 

On 20/06/2015 at 9:37 PM, SydneySideSteveSomewheres said:

 

Assuming that the ram is Non-ECC (error-correcting code memory, which is mostly found in servers and workstations) then it will change to the lowest MHz range that they both function with. If you use a program like CPU Z or AIDA64 you can see the ram timings and whichever they both have this will be the operational range.

Included is a screen grab in which the voltage was changed, as this is a "given" i.e. that you are more than capable of addressing this.

You can see that both the different manufacturers' ram operates in differing ranges also that they do not line up exactly even when the MHz frequencies are the same. This is mentioned as ram will find it's own timing and this may not be the 1333MHz range you require.

If they do not have a MHz range where they both can operate then you could find that the computer will not boot, and to fix would be just simply a matter of removing a stick of ram.

 

 

http://www.cpuid.com/

http://www.aida64.com/

 

 

 

[Imakuni]

5 hours ago, say_wat_now said:

The 6700k memory controller supports DDR3L-1333, DDR3L-1600, DDR4-1866, and DDR4-2133 memory.

 

So say I put in a 2400MHz stick of RAM with a 6700k processor. Will it be bottlenecked down to 2133MHz? And if it is I can overclock it to support 2400MHz?

 

If I overclock my RAM through the UEFI am I modifying the memory controller support or am I modifying the speed of the actual RAM stick?

 

i confuse, pls halp thnx

Let me tell you a secret: there's no such thing as a "2400"mhz stick of RAM. It doesn't exist. There's only 2133mhz DDR4. Every other kit higher than that is just rated to be OCed to that ammount, but it's still plain regular 2133 RAM.

 

With that said, though, just because a kit was found out to be stable at a ludicrous 4000mhz, that doesn't mean that the IMC on the CPU can actually handle such speed. The vast majority of Skylake CPUs should be able to hit 3000~3200mhz (if not literally every single CPU), but past that point is going to be luck of the draw as far as IMC goes.

 

So in sum, you are OCing 2 things at once: the IMC and the RAM modules.

[typographie]

8 hours ago, say_wat_now said:

So say I put in a 2400MHz stick of RAM with a 6700k processor. Will it be bottlenecked down to 2133MHz? And if it is I can overclock it to support 2400MHz?

If you don't change anything in the BIOS, yes. 2133 MHz is the JEDEC default specification for DDR4, so that's what it will be when you first turn on the PC. If you have a Z170 motherboard, your memory is advertised as DDR4-2400, and the memory supports XMP, you can enable the XMP profile in the BIOS and it should auto-detect the proper settings for 2400 MHz.

 

Since this is technically overclocking, some CPUs may be capable of less than others. 2400 MHz is quite low for DDR4 and will likely work for nearly anyone, but most motherboard and memory manufacturers will not guarantee results at very high clock speeds.