G.Skill Hits 5GHz With Overclocked Air-Cooled Dual-Channel Memory Kit

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AgentLozen

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DDR4 @ 5000MHz is a really cool acomplishment.

The question is - what do you do with 5000MHz DDR4 memory? What sort of application benefits from it?

When we hear about overclocked CPUs or graphics cards, it's easy to imagine the benefit of those clock speeds. That's not the case with system memory though. DDR4-3200 provides all the bandwidth any desktop user could need.
 

Dantte

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Overclocking a CPU is pretty much the whole reason for high-speed memory. This is the whole purpose behind my coffee build: get some good memory, supporting MB, and you can overclock a relatively cheap processor to a great processor with ease!
 

derekullo

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I just learned how to calculate the true latency of ram.

Ok well its just A*B=C, but it wasn't immediately obvious lol.

Let me know if the math is wrong or if this is just completely wrong ...

http://www.crucial.com/usa/en/memory-performance-speed-latency


5000/2 = 2500

1/2500(ddr4) = a cycle time of 0.4 nanoseconds.

https://en.wikipedia.org/wiki/CAS_latency

Which closely matches the CAS for DDR4-4800 of 0.417 nanoseconds


0.4 nanoseconds x a cas of 21 = a true latency of 8.4 nanoseconds.


To put this in perspective lets focus on the original timings of the ram to see if this is faster or slower.

The original G.Skill Trident was a DDR4-4700 with a CAS of 19

4700/2 = 2350

1/2350 = a cycle time of 0.425 nanoseconds

0.425 nanoseconds x a cas of 19 = a true latency of 8.075


Meaning the original ram was quicker by about 4% due do its tighter timings.

It is still an accomplishment, as mentioned earlier, but I guess this is why they haven't pushed the 5000 into marketing.

If they drop the cas down to 20 with the 5000 overclock that would come out to

0.4 nanoseconds x a cas of 20 = a true latency of 8.00 nanoseconds, about 1% faster than the marketed overclock and timings.
 

BulkZerker

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@AGENTLOZEN

"No one will ever need more than 16 megabytes of ram." We will certainly appreciate the speed sooner rather than later. Especially those pushing the limits of raven ridge APUs.
 

mischon123

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It will get interesting when more processing is moved on ram dies and running at 5khz. As it is DDR4 is pretty much as fast as it can get at 4khz.
 


It's not just the RAM speed when talking about AMD CPU's. We know the infinity fabric in Ryzen and Threadripper scales with RAM speed. I would love to see some benchmarks showing several RAM speeds, including this one so see jsut how much difference it truly makes.
 

Ninjawithagun

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Unfortunately, Intel's use of cheap TIM greatly limits the overclocking potential. The only real solution to resolve this issue is to delid and go liquid metal, effectively voiding the warranty of your shiny new processor. Sad Intel, sad :(
 

AgentLozen

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I've read that memory speed makes a big difference with Ryzen CPUs. But I've also read that they get unstable after a certain speed. I'm looking forward to finding out how AMD has changed Ryzen 2 regarding infinity fabric latency and memory speed.
 
This 5k mhz sticks is purely for record breakers. Expect a huge price premium. Also, stable system doesn't mean prolonged stable usage. So ur ram stick life will be also be short with the heat output @ 1.45v

But hey, it got rgb!
 
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