Intel i7-8700K Coffee Lake Memory Benchmark Analysis

[Sasqui]

Fair enough, but we can´t conclude that higher frequency RAM isn´t worth for gaming. Depends on your usage, and again, minimumfps/0,1% are too important on a RAM Gaming test. Also you can´t get CAS 14 kits that easy, not at 3200mhz for sure. You can downclock 3800mhz CAS19 to 3200mhz CAS 14 tho, but that would cost the same money.

I think in W1zzards conclusion he was saying in general there's a point of diminishing returns with really fast/expensive memory. Lots of money with not much gain. I didn't see any conclusion specifically about games per se .... but I guess you could read it that way.

 

[Frick]

Clearly? Clearly you are accepting the results without thinking too in detail about them. There's a reason W1zzard himself contradicts them in this very review.

Hint: Encode doesn't use intercore communication much at all.

Other hint: What does infinity fabric do?

So under what scenario and in what applications do you get the meaningful increase in performance with a faster interconnect? Honest question.

 

[ZenZimZaliben]

Wow this is a great review. I just ordered 32GB G.Skill 3200 CAS 14 for my new build. Looks like it was a good choice.

 

[Camm]

A very solid, informative article. Thanks for the work!

 

[R-T-B]

So under what scenario and in what applications do you get the meaningful increase in performance with a faster interconnect? Honest question.

Games and anything in which the threads must know what the other one is doing.

 

[Frick]

Games and anything in which the threads must know what the other one is doing.

But there's not much gain to be had, if you go for at least 2800Mhz.

 

[R-T-B]

But there's not much gain to be had, if you go for at least 2800Mhz.

True. Diminishing returns. I was only saying it is greater than the Kaby/Coffee Lake Uncore's gains.

The real penalty is when you starve Ryzen of mem bandwidth, not saturate it.

 

[Deleted member 172152]

Coffeelake seems to care a lot less about memory than even previous Intel architectures. Strange.

I still think fast RAM is worth it if you have budget left after perfecting the rest of your build, even if it's only for peace of mind that when RAM IS a bottleneck, it won't bottleneck quite as much and of course bottlenecking tends to have exponentially decreasing performance, so even slightly better RAM could potentially make a fairly big difference.

Just don't go for 100 bucks more expensive RAM, but 20 or 30 bucks extra should get you a fair bit faster RAM.

 

[noname00]

I often just leave many applications opened, chrome has at least 50 tabs opened all the time. It would be interesting to see the performance impact of ram speed while having many apps run in parallel. For example gaming while encoding something with handbrake (using a single thread for that), listening to music from youtube using a browser with 40-60 tabs opened.

Thanks for the review

 

[Melvis]

With those results been all over the place I would just go with the cheaper RAM, wouldnt waste your money on higher speed stuff.

 

[Tsukiyomi91]

This is a good review, @W1zzard. Very detailed & highly informative.

 

[Tsukiyomi91]

@Melvis it all depends on who will build it. I find the sweet spot between 2666MHz to 3866MHz. 3200 is a good place to start, though 2666 is more than enough for the mainstream user.

 

[Melvis]

@Melvis it all depends on who will build it. I find the sweet spot between 2666MHz to 3866MHz. 3200 is a good place to start, though 2666 is more than enough for the mainstream user.

I agree, I wouldnt go the slowest stuff but wouldnt go the fastest ether, go with middle of the road like you said the 2666 or at most 3200, there is a way bigger difference when it comes to AMD Ryzen thats for sure.

 

[Tsukiyomi91]

Ryzen would benefit a much more higher speed kit, considering it's not really working in unison like Intel yet. Still a long way for Ryzen to be on equal grounds with a similarly built Intel system, but I know it has potential to be better.

 

[THU31]

The main thing that matters in gaming benchmarks is the minimum framerate. Memory bandwidth is most important in CPU intensive scenarios. You should watch some Digital Foundry videos where they compare memory speeds in various games. Watching the current framerate will show you just how big a difference it can make. Average framerate basically means nothing.

 

[Dolfff]

Very usefull article, thank you so much. It shows very clearly that it doesn't make much sense to go extreme with memory on a stock clocked 8700k. 3200MHz with tight timing looks like the sweetspot for more demanding users.

However, I would really like to see this test repeated for a 8700k clocked at 5.2 GHz (which seems a stable and useable oc for some 8700k's out there). That would in fact be more realistic because I don't think many people are going to oc their memory only, without oc'ing there cpu. I assume that faster memory settings make more sense if CPU is overclocked. I would really like to see that confirmed (or busted) as to determine the "sweetspot" for such a setup. Meanwhile, can someone reflect on my assumption?

 

[Manu_PT]

8700k clocked at 5,2ghz stable oc for most? I highly doubt that... some don´t get past 4,8ghz if you check the web.

 

[R0H1T]

Very usefull article, thank you so much. It shows very clearly that it doesn't make much sense to go extreme with memory on a stock clocked 8700k. 3200MHz with tight timing looks like the sweetspot for more demanding users.

However, I would really like to see this test repeated for a 8700k clocked at 5.2 GHz (which seems a stable and useable oc for most 8700k's out there). That would in fact be more realistic because I don't think many people are going to oc their memory only, without oc'ing there cpu. I assume that faster memory settings make more sense if CPU is overclocked. I would really like to see that confirmed (or busted) as to determine the "sweetspot" for such a setup. Meanwhile, can someone reflect on my assumption?

You'll need water cooling in many cases for that, a real good WC setup for some at that speed.
5.2 is a real outlier & hardly warrants a separate (re)bench though if you're doing a max OCing review or something, it makes sense.

 

[TheHunter]

Thanks, was a interesting read. I kinda expected bigger difference though.


I saw MT engine games (Resident evil series and lost planet2) can have big difference too, they're old now but still very cpu/memory/driver/dxapi dependent and can show difference quick. Ffxiv series also, crysis, x3tc..

 

[Dolfff]

8700k clocked at 5,2ghz stable oc for most? I highly doubt that... some don´t get past 4,8ghz if you check the web.

"Most" was indeed an exaggeration, sorry for that. I changed it to "some".

 

[Dolfff]

You'll need water cooling in many cases for that, a real good WC setup for some at that speed.
5.2 is a real outlier & hardly warrants a separate (re)bench though if you're doing a max OCing review or something, it makes sense.

Okay, 5.0 GHz then. Or 4.8. It's quite easy to do that without extreme measures (although an AIO WC is advised of course). This is not the point though. The point is that this is an unlocked processor that can very easily be overclocked (and many will do that) and it would be really interesting to see if advantages of faster memory are more visible in such a setup.

 

[R0H1T]

Okay, 5.0 GHz then. Or 4.8. It's quite easy to do that without extreme measures (although an AIO WC is advised of course). This is not the point though. The point is that this is an unlocked processor that can very easily be overclocked (and many will do that) and it would be really interesting to see if advantages of faster memory are more visible in such a setup.

Fair to say that I don't recall (m)any apps which are memory sensitive, even for games there are only a handful viz F1 IIRC. Outside of AVX512 intensive tests the Intel CPU have not been affected by memory, bandwidth or latency for instance.
Would be interesting to see if there are any AVX2 heavy tests which can show the effects of memory scaling or latency for KBL & CFL.

 

[Prima.Vera]

So, basically anything above 2666 14-14-34-1T is useless (IOW, the price increase doesn't correspond with performance increase).

I would say 3200Mhz is now the sweet spot, specially if you have tight timings.

 

[EarthDog]

For intel...

...3200 is almost max for amd... some systems wont reach it..

 

[efikkan]

DDR4-2666 is not going to bottleneck such systems without a very specialized workload. Just buy the most reasonable priced memory at >= 2666 MHz, and put the rest of the money in a GPU.