Intel Sunny Cove Successor Significantly Bigger: Jim Keller

[Chrispy_]

RAM speed matters little to nothing for gaming. Gaming is not bottlenecked by memory bandwidth, and "faster" memory really only improve bandwidth, not latency.

While Skylake have improved clocks a lot over Sandy Bridge, especially with "aggressive" boosting, the CPU front-end improvements have also helped a lot. It's important to remember that IPC is a measure of "arbitrary" workloads, and many things affect IPC. One of the reasons why Intel still have an edge in gaming is a stronger front-end, while AMD have higher peak ALU/FPU throughput in some cases, both of which affect IPC, but only the first really affect gaming.

Like Danbert and Midland, I strongly disagree with you on this. You're comparing Sandy (DDR3-1333MHz max spec) with modern platforms that manage a minimum of ~2.5x the bandwidth and significantly lower latency at the same time.

Typically, RAM bandwidth is one of the leading contributors to low minimum framerates and there is no shortage of articles and videos going back a decade or so that make this painfully obvious. I must have watched and read over a hundred mainstream videos on this topic alone.

Who cares about average framerates when their 1% low and 0.1% low framerates are absolutely tanking performance when it matters?

 

[efikkan]

Like Danbert and Midland, I strongly disagree with you on this. You're comparing Sandy (DDR3-1333MHz max spec) with modern platforms that manage a minimum of ~2.5x the bandwidth and significantly lower latency at the same time.

Perhaps I could have been a little more precise. Yes, 1333 MHz vs 2666 MHz in today's games would impact performance somewhat. Around 2133-2400 MHz it starts to flatten out, and beyond 2666 MHz there are few significant differences (for Intel CPUs). My point that I didn't get across well enough is that memory speed matters much less than people think, and even the performance impact between 1333 MHz and 2666 MHz is usually only a few percent.

But no, memory latency haven't changed in the last 10+ years.

Who cares about average framerates when their 1% low and 0.1% low framerates are absolutely tanking performance when it matters?

I agree that consistency is much more important than average frame rate, no issue there.

 

[londiste]

How much memory speed matters depends on application or game. At least among games there are definitely examples that rely on memory bandwidth and get decent improvements from faster memory, far more than a few percent.

 

[Chrispy_]

But no, memory latency haven't changed in the last 10+ years.

DDR3-1333 CL8 is 6.00ns of CAS latency, and that was the high-end stuff back in 2009 with a hefty premium.
DDR4-3200 CL14 is 4.37ns of CAS latency, and that's today's cheap stuff. You can buy 4600 CL17 if you want to pay the premium tax!

So yeah, we're probably looking at about a 50% improvement in latency alone if you take a mid-range kit from now and 10 years ago and compare the raw latency in nanoseconds. By saying memory latency hasn't changed in a decade is an insult to all the work and progress Samsung, Hynix, and Micron have made over the last few generations.

Ryzen loves faster RAM.
Intel loves faster RAM.

Even in 2017 on an i7-7700K, 3200MHz seemed to be the sweet spot with several mainstream titles doing up to 25% worse when dropping from 3200 to 2666. As far as most reviewers and youtubers are concerned, using less than DDR4-3200 is a bad idea these days because you're losing out on CPU performance. It doesn't matter if that's latency or bandwidth, the results are just worse with slower RAM.

 

[efikkan]

DDR3-1333 CL8 is 6.00ns of CAS latency, and that was the high-end stuff back in 2009 with a hefty premium.
DDR4-3200 CL14 is 4.37ns of CAS latency, and that's today's cheap stuff. You can buy 4600 CL17 if you want to pay the premium tax!

So yeah, we're probably looking at about a 50% improvement in latency alone if you take a mid-range kit from now and 10 years ago and compare the raw latency in nanoseconds. By saying memory latency hasn't changed in a decade is an insult to all the work and progress Samsung, Hynix, and Micron have made over the last few generations.

I'm sorry, but you are completely wrong when it comes to latency.
You can read about memory latency here.
Access time of an arbitrary address in DRAM is about ~50ns, with memory controller overhead it's about ~70-90ns as you can see here. So when you compare memory with different CAS latency with is 1.5-2ns quicker, it's not 50% quicker, more like ~2-3% quicker (and that's assuming you are able to actually run it on the best case non-JEDEC speeds they put in the spec sheet).
As I said, DRAM latencies haven't changed much changed a lot since the old Pentiums, which was still around ~>80ns.

Ryzen loves faster RAM.
Intel loves faster RAM.

Zen/Zen2 benefits from faster memory frequencies because other timings are tied to it internally, so that's only indirectly.
As you increase the memory speed, you generally only get more bandwidth, as CAS latency has to be increased as the clock increases due to the inherit latencies in DRAM.
And if bandwidth were a bottleneck for gaming, gamers would all buy HEDT CPUs with quad/hex/octa channel memory, that's the easiest way to get a lot of memory bandwidth.
Also, the preliminary specs for upcoming DDR5 expects higher latencies than DDR4.

 

[Chrispy_]

I'm sorry, but you are completely wrong when it comes to latency.
You can read about memory latency here.
Access time of an arbitrary address in DRAM is about ~50ns, with memory controller overhead it's about ~70-90ns as you can see here. So when you compare memory with different CAS latency with is 1.5-2ns quicker, it's not 50% quicker, more like ~2-3% quicker (and that's assuming you are able to actually run it on the best case non-JEDEC speeds they put in the spec sheet).
As I said, DRAM latencies haven't changed much changed a lot since the old Pentiums, which was still around ~>80ns.

Fair enough. I was just going on CAS latency x clock interval.

In terms of memory improvements though, I don't think it even matters that overall memory latency hasn't changed much. People can argue hypothetical theory all day, but in the real world, in real applications and real games, a significant portion of performance can be attributed to faster RAM, with a simple litmus test of "put in slower RAM and watch the performance vanish".

 

[londiste]

DDR3-1333 CL8 is 6.00ns of CAS latency, and that was the high-end stuff back in 2009 with a hefty premium.
DDR4-3200 CL14 is 4.37ns of CAS latency, and that's today's cheap stuff. You can buy 4600 CL17 if you want to pay the premium tax!

This is not a good comparison. 2009 was early in DDR3 lifecycle and while a common module was DDR3-1333 there definitely were DDR3-1600 and faster modules available by the end of DDR3, you could get DDR3-1866 or DDR3-2133. DDR4 is much closer to the end of its life cycle by today. Look back to similar place in its life cycle a your DDR3 example and an average module was DDR4-2400

DDR4-3200 CL14 is most definitely not cheap stuff. DDR4-3200 CL16 costs almost half of what CL14 costs.

And if bandwidth were a bottleneck for gaming, gamers would all buy HEDT CPUs with quad/hex/octa channel memory, that's the easiest way to get a lot of memory bandwidth.

Gamers did buy HEDT CPUs for a while and there are clear benefits even in gaming from more memory bandwidth. However, today the HEDT CPUs are overkill in terms of core count on one hand and/or not the best organization of inter-core communication for latency and this has clear negative effect on gaming. Both Intel's mesh CPUs and Threadrippers have the same problem here. Zen2-based Threadrippers might bring a change to this, hopefully.

Also, the preliminary specs for upcoming DDR5 expects higher latencies than DDR4.

As was the case with DDR2, DDR3 and DDR4

 

[Chrispy_]

This is not a good comparison. 2009 was early in DDR3 lifecycle and while a common module was DDR3-1333 there definitely were DDR3-1600 and faster modules available by the end of DDR3, you could get DDR3-1866 or DDR3-2133. DDR4 is much closer to the end of its life cycle by today. Look back to similar place in its life cycle a your DDR3 example and an average module was DDR4-2400

I only picked those values because they are the Intel and AMD spec of Sandy Bridge and Zen 2 respectively to indicate the ~10 year difference. (it's 8 years, 9 months, actually).

As for pricing, I suspect that's just regional variation. 3200 14-16-16 is guaranteed on Samsung B-die It shouldn't be expensive and I certainly haven't paid much of a premium for it in the last quarter. You do have to read between the lines a bit because JEDEC-spec 3200 (PC4-25600) ranges from CL22 to CL20 and it's practically impossible to even buy RAM that slow. Even the lowest-grade Micron A-die or Samsung B-die will likely meet AMD's recommendations of 3200 CL14. It's not as if the XMP info in the SPD is particularly helpful either because it's not optimised for Ryzen and even across different generation of Intel DDR4-compatible CPUs there's a lot of variation in their RAM tolerance and IMC quality.

What I tried to say in my previous post is that none of these minor latency or timing details really matter. If you take any modern processor on today's mainstream DDR4 (somewhere around 3200) you are going to see drastic performance loss if you swap in much slower RAM, which brings us back to the original point of this discussion - that significant IPC gains made in the last decade are at least partly attributable to the improvements in DRAM speed and not something Intel can claim as true IPC gains. We all know that Haswell benefitted from a RAM overclock, despite the spec only being officially capped at 1600MHz.

 

[londiste]

It is not so much the difference in years but a difference in where the RAM type is in its life cycle. DDR3 came out in 2007 and 2009 was pretty early in its life cycle. For DDR4 that came out in 2014 the same timeframe would be somewhere 2016-ish. CPU IMC spec's especially when it comes to Intel is probably a bad baseline.

You are also talking about memory overclocking here. Yeah, B-dies do 3200 CL14 but out-of-box spec module prices are a bit different thing. Looking at prices in Europe, 2x8GB CL16 will cost about 70€ and CL14 about 130€. Same relative difference applies to other sizes as well. JEDEC spec is a bit of a different thing because it states 1.2V as working voltage and low voltage is what gives you 3200 CL18-22.

How much of the speedup is attributable to RAM speedup is not a single question. There are benchmarks that really don't care. Cinebench (especially R15) is a very good example.

 

[yeeeeman]

Why just now they (Intel) rejoining the inovative part of the scene , as ever since "Skylake" , it's as if Intel was in retirement cashing pension coupons or viewed another way , a multy year sabbatical.
So , in another parallel universe, I am safekeeping my 2 entry-level Skylake cpu's one being a Pentium spec whilst the other is a Celeron spec , having them donated to museums all the while story talking my children/grandchildren on how the x86 cpu's "war's" were "fought" and reminiscent of the era's when Intel was top dog in most of those , until "Ivy-Lake" .

"Good night and faa iuu"

I guess you don't read news. They had MASSIVE issues with 10nm. That is why.