Wednesday, May 27th 2020

PSA: There are Two Steppings of Non-K 10th Gen Core i5 in Circulation, Only One Comes with STIM

There are apparently two steppings of the 10th generation Intel Core i5 desktop processor in circulation, and the two have major physical differences, even if their specifications are identical per SKU. These are Q0 and G1. The Q0 stepping of the 10th gen Core i5 is based on the 10-core variant of "Comet Lake-S" silicon, the 200-odd mm² die, which comes with Intel's die-thinning innovation, and more importantly, soldered thermal interface material (STIM). For these chips, four cores on the 10-core die are disabled by Intel to carve out the 6-core/12-thread Core i5 SKU. The G1 stepping, on the other hand, is based on the 6-core variant of "Comet Lake-S," which is similar in design to the 6-core "Coffee Lake" die. The G1-stepping chips lack STIM, and use a thermal paste.

What's more, Q0 and G1 steppings have different SPEC codes. For the Core i5-10400F, the Q0 stepping variant's SPEC code is "SRH79" and the G1 stepping variant's code is "SRH3D." The underside of the processor's package looks different between the two steppings (pictured below). You won't be able to tell the underside of the package through the little window in your processor's retail package, but the SPEC code is printed on the IHS. There's no geographic marker as to which stepping is found in what particular market. Both steppings appear to be distributed uniformly, wherever available. Since Intel is using this stepping-level differentiation only among non-K SKUs, we don't expect the two to have any different performance, but possibly different thermals.
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12 Comments on PSA: There are Two Steppings of Non-K 10th Gen Core i5 in Circulation, Only One Comes with STIM

#1
Vayra86
The plot thickens... or maybe not. You never know until you check

badum tss
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#2
ppn
I knew it, CPUZ says Q0/G1 for a reason, the same goes for 10900K.
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#3
The Quim Reaper
Can see it now,

When these eventually come onto the used CPU market, every seller is going to be asked which stepping they have and it will mean the difference between sale or no sale, or sale at a much reduced price.
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#4
CheapMeat
I hate that you have to play the lottery basically.
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#5
DarthFK
The G1 stepping feels like the unsold stock if i7-8700 or the same fab process to cut the costs, though only on non-k SKUs (for now or...?)
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#6
tabascosauz
AT talked about this on review launch day, that the 10600K is a fused 10-core but the other i5s are native 6-cores. Makes me wonder if the 6-core dies are diverted from mobile Comet Lake production, cache setup between the 10750H and 10400 are identical.

The 6-core isn't desperately in need of STIM to stay alive unlike the 10-core, so this makes for a very interesting comparison. I suppose it's clear to see why the 10600K and 10700K took after the 10-core die instead; Intel obviously didn't want to put in the extra effort on a blatant stopgap generation to R&D anything other than a single piece of silicon (the 10-core), so one of the highlight features, STIM + thin die, only made it to the 10-core and everything higher end in the lineup is based off of one product.

If based off mobile dies, it would be a very peculiar binning proposition: shitty? but fully enabled 6-cores vs shitty? cut down 10s.

Placement of caps on the bottom of G1 look similar to Coffee Lake 6-core, but also not quite the same. Comet Lake has 1 or 2 extra hardware mitigations, but they otherwise are identical, and it's not like any 10400 or 10400F will be able to test the frequency potential of the 6C anyways.
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#7
1d10t
On team red they secretly upgraded their first gen to 12nm, meanwhile on team blue...
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#8
Vayra86
Know what you buy

"Marines on stims benefit from greatly increased speed and reflexes, but are subject to long-term side effects including and not limited to insomnia, weight loss, mania/hypomania, seizures, paranoiac hallucinations, internal hemorrhaging, and cerebral deterioration. Nonetheless, both commanders and the marines themselves stand by the use of stims as essential to their continued survival and effectiveness on the battlefield."

- The uses and risks of stimpacks

starcraft.fandom.com/wiki/Stimpack

Another fun one. In the original vanilla Starcraft (paper) manual it says Stims lengthen the battlefield lifetime of Marines by as much as "10 seconds"
Posted on Reply
#9
tabascosauz
Vayra86
snip
*tsssss* ah that's the stuff *tsssssssss* OHHH YEAHHH

Brood War marine best marine
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#10
zlobby
Typical intel. Why I'm not surprised?
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#11
Caring1
The Quim Reaper
Can see it now,

When these eventually come onto the used CPU market, every seller is going to be asked which stepping they have and it will mean the difference between sale or no sale, or sale at a much reduced price.
So far it's only showing the i5-10400 and i5-10400F version as having both steppings, so shouldn't be an issue for gamers and those chasing performance.
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#12
Berfs1
lol yall finally realized the stepping correlates to the actual die

docs.google.com/spreadsheets/d/1c-UyYACl4_bmsBb4CFp1RI0A1lkA2GJUjpwM7E9zbAE/edit?usp=sharing

Head over to the LGA1200 tab and you will find all the information :)
DarthFK
The G1 stepping feels like the unsold stock if i7-8700 or the same fab process to cut the costs, though only on non-k SKUs (for now or...?)
Not true, two different dies. G1 and Q0 are unique to 10th gen while B0 stepping, which the i3-9100F has a variant for (other one is U0), is actually the Kaby Lake quad core die. Ever wondered why 8th/9th gen was able to work on 100 and 200 series motherboards and vice versa? Dies were the same. Naturally, they should have worked on LGA1151 without mods. Though, LGA1200 is a bit different, but I think someone will still find a way to make it work.
Caring1
So far it's only showing the i5-10400 and i5-10400F version as having both steppings, so shouldn't be an issue for gamers and those chasing performance.
My assumption is, Intel used the lower binned Q0 dies for the 10400/F as well as G1 dies for the sole purpose of yields. Because they know a lot of people will be going for the 10400F, 10600K/F, 10700F, and 10900K/F.

Oh also, aside from the 10400/F, the 10600K/F are Q0 dies and NO G1 variants. So they come from the lower binned Q0 dies, which is why if you remember that chart MSI posted about overclockability being higher on the i7/i9s, well, that's why. The 10600K/F is the lowest bin Q0 dies, and the chances of getting a good one is next to none (good as in I think 5.2 GHz)
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