Wednesday, April 7th 2021

Gear 1 can Lead to Performance Loss on Intel "Rocket Lake" 11th Gen Processors

In the course of our Core i5-11400F "Rocket Lake" processor review, we discovered that the Gear 2 memory mode has the potential to offer higher performance than Gear 1. The Gear 1 mode runs the memory frequency and memory controller frequency in 1:1 sync, while the Gear 2 mode runs them at 1:2, meaning that the memory controllers run at half the memory frequency, allowing you additional memory overclocking headroom. At lower, more stable, memory frequencies, it should be logical to use Gear 1. Our testing springs some surprising results.

Overall, a stock Core i5-11400F paired with DDR4-3733 MHz memory, was found to be 1.5% faster with Gear 2, when averaged across all our CPU tests, compared to Gear 1 at the same 3733 MHz frequency. Gear 2 was 3.42% faster in Cinebench R23 multi-threaded, and a staggering 6% in MySQL. Across rendering and media workloads that scale across all cores, we find Gear 2 faster by 1-3%. It's only with less parallelized workloads such as gaming, where we see Gear 2 lag behind Gear 1, though not by much. In our i5-11400F review, we show that by running your processor in Gear 2, you're making your memory controllers pull less power, freeing up power budget for the CPU cores, translating into the nT performance gains we see here. We discovered that the uncore can pull anywhere between 5 to 10 W more power in Gear 1 mode. This is valuable power eating into the already constrained power-budget of this 65 W TDP chip.

Read the Intel Core i5-11400F TechPowerUp Review
This behavior wasn't spotted in our launch-day i5-11600K and i9-11900K reviews; as the i5-11400F is our first Rocket Lake with a 65 W TDP. We expect the disparity between Gear 2 and Gear 1 at stock settings to only grow wider with higher core-count 65 W models, such as the Core i7-10700/F and the i9-11900/F. Gear 1 claws its way back to the top when you engage power limit overrides offered by motherboards. These overrides vary from motherboard to motherboard, but they generally free up more power budget for your CPU cores to sustain their boost frequencies better. For more data and commentary, be sure to catch our Core i5-11400F review.
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42 Comments on Gear 1 can Lead to Performance Loss on Intel "Rocket Lake" 11th Gen Processors

#26
W1zzard
stimpy88
Intel is so against the wall that they can't run the memclock at full speed when using fast memory, due to the ancient manufacturing process they are forced to use, the cores need every Watt they can get their hands on just to offer almost AMD like performance!
Very interesting theory. So maybe that's why Gear 2 exists, so that low-watt SKUs can still use fast memory. Imagine a 35 W -T CPU running with the MC using up 15 W
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#27
nguyen
W1zzard
Very interesting theory. So maybe that's why Gear 2 exists, so that low-watt SKUs can still use fast memory. Imagine a 35 W -T CPU running with the MC using up 15 W
Isn't Ryzen 3's MC located on the IO die which is made on GF 12nm? doesn't make sense that Ryzen MC is more efficient than Intel MC.
Also can you try messing with the Ring Cache ratio? they could improve/degrade efficiency to some degree.
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#28
Anymal
I guess my car has Intel Inside as in Gear 2 its faster than in Gear 1.
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#29
Vanny
They massacred the IMC in this gen so much it makes my Zen 2 IMC look good
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#30
W1zzard
nguyen
Isn't Ryzen 3's MC located on the IO die which is made on GF 12nm? doesn't make sense that Ryzen MC is more efficient than Intel MC.
Efficiency is barely a function of the process, what matters is the chip/circuit design and algorithms. Look at Navi 1x vs 2x
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#31
Wirko
Anymal
I guess my car has Intel Inside as in Gear 2 its faster than in Gear 1.
If it's sometimes, but not always, faster in Gear 2 then it sure has Intel Inside.
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#32
Minus Infinity
I suppose technically it's news, but gee so much time wasted reporting about an utterly crap product that should have never been released. Why delve into the minutia of an evolutionary dead end. Roll on Alder Lake and Zen3+/4.
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#33
W1zzard
Minus Infinity
Why delve into the minutia of an evolutionary dead end
You think they're designing yet another new memory controller for Alder Lake?
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#34
owen10578
Well just run it at the unlimited TDP mode or whatever raised TDP the motherboard allows. Running these at 65W is really dumb imo.
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#37
Prima.Vera
Why_Me
www.techradar.com/news/intel-rocket-lake-allows-for-new-world-record-ram-overclock-of-a-staggering-7156mhz
The completely impractical method that the MSI overclockers used to hit the dizzy heights of 7,156MHz included the obligatory liquid nitrogen cooling, as well as CAS Latency being upped to 58 (from 19 at stock with this RAM).

Note that it was also a single stick of RAM, so single-channel rather than dual-channel (in real world situations, the latter is the way you want to be running system memory for the best performance, meaning two 4GB sticks rather than a single 8GB module as is the case here). The 11900K CPU was also massively underclocked (to just under 1.5GHz) in the record-beating rig.
on topic:

So let me get this straight.
If I buy a 11900K CPU, a top Z590 mobo, and 2 sticks of DDR4-4200 RAM, am I forced to run only in G1 in order to keep the 4200 speed on the RAMs??
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#38
W1zzard
Prima.Vera
and 2 sticks of DDR4-4200 RAM, am I forced to run only in G1 in order to keep the 4200 speed on the RAMs??
You must run in Gear 2 mode, because the memory controller in Gear 1 won't be able to handle that speed, not even 3800
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#39
Prima.Vera
I'm a little confused. The Nexus guy also teste G1 vs G2 and concluded that G2 is actually the slowest one:

So, which is it?? :)
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#40
W1zzard
Prima.Vera
that G2 is actually the slowest one
Let me summarize the news post: normally gear 1 is faster than gear 2. but gear 1 uses A LOT more power. this power eats into the CPU math cores' power budget. this causes power throttling much earlier, and thus leads to a loss in performance

That's why we posted this, because everyone tested on high-powered CPUs and came to the conclusion "Gear 1 is best"

All non-K RKL CPUs are affected, no point buying more expensive memory for Gear 1, unless you manually increase the power limit at the same time
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#41
Prima.Vera
Thank you W.
What intel did with this series is a disaster imo, hopefully the new 12th Gen won't have this gear crap anymore.
Or will they...?
Posted on Reply
#42
Wirko
Prima.Vera
Thank you W.
What intel did with this series is a disaster imo, hopefully the new 12th Gen won't have this gear crap anymore.
Or will they...?
Well, what kind of memory speeds do you expect to see on Alder Lake desktop systems? Around 4500 MT/s? Around 5000? Around 5500?
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