More than 2133 dual channel == bottleneck ?

Mkazem

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Jul 18, 2016
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Ive read somewhere in comments written how to calculate maximum memory bandwidth:

" Memory Bandwidth = Memory Base clock (MHz) x I/O Cycles (the number next to DDR) x Transfers Per Clock (2 for all DDR because Double Data Rate) x RAM bus (64-bit lane for all DDR so far) x Number of Channels (2 or 4). "

Here you can see maximum memory bandwidth of 6700 skylake processor which is 34GB/s.

http://ark.intel.com/products/88196/Intel-Core-i7-6700-Processor-8M-Cache-up-to-4_00-GHz

Say i have two 2133 DDR4 memory.

266 * 2 * 4 = 2133 (memory clock)
2133 * 64 * 2 = 273024 (transfer rate)
273024 / 8 / 1000 = 34.12GB/s (convert to GB/s)

As you see it reached the maximum bandwidth specified for intel 6700 processor.

So does it mean i dont get more speed having anything more than dual channel 2133 mhz??

Any reason to buy dual channel 2400/2800/3200 etc for skylake processors? (other than good looking heat sink ;) )

(TBH im going to buy memory which fits with theme of my build :) but im just wondering!)

Thanks in advance
 
Solution
you made it more then it as to be. on ddr3 ram 1600 speed is 800. 2133 is 1066.
the 2133 as it base speed is faster can move data to and from cpu faster then the stock speed.
there are few news clips on google "intel cpu and fast ram"
the newer intel and amd cpu do run better with faster ram to a point.
that point is cost and voltage and heat.
ddr4 memory controler spec is 1.25 at 2100.
you can run faster ram just try and keep it at 1.25. the max voltage for the ddr4 ram controller is 1.35v.
when you run faster ram the timming between the cpu and ram changes. that why intel has xmp profile for ram.
you made it more then it as to be. on ddr3 ram 1600 speed is 800. 2133 is 1066.
the 2133 as it base speed is faster can move data to and from cpu faster then the stock speed.
there are few news clips on google "intel cpu and fast ram"
the newer intel and amd cpu do run better with faster ram to a point.
that point is cost and voltage and heat.
ddr4 memory controler spec is 1.25 at 2100.
you can run faster ram just try and keep it at 1.25. the max voltage for the ddr4 ram controller is 1.35v.
when you run faster ram the timming between the cpu and ram changes. that why intel has xmp profile for ram.
 
Solution

The i7-6700 supports up to 2 memory channels, so you don't really have the option of more than dual. If you want quad channel memorry you need to look at the "extreme" or "high-performance" processors; their part numbers look like i7-x8xx or i7-x9xx (e.g. i7-6900k). You get more PCI-Express lanes with those processors too.