Thursday, August 31st 2017

AMD Ryzen Threadripper 1900X Core Configuration Detailed

At its pre-launch media conference call for the Ryzen Threadripper 1900X, AMD mentioned that the chip has been carved out from the common 4-die EPYC MCM using a "4-0-4-0 diagonal configuration," which led to some confusion as to which cores/dies AMD disabled to carve out the $549 8-core HEDT processor. The company shed some light on this matter, responding to questions from TechPowerUp.

It turns out, that the Threadripper 1900X features an entire CCX (quad-core CPU complex) disabled per active die on the multi-chip module, so the CCX that's enabled has 8 MB of L3 cache; and access to the die's entire uncore resources, such as the dual-channel memory controller, PCIe root complex, etc. With two such active "Zeppelin" dies, the Threadripper 1900X ends up with 8 cores, 16 MB of L3 cache, a quad-channel memory interface, and 64 PCIe lanes.
The decision to disable an entire CCX, rather than doing something similar to the "Zeppelin" die as with the Ryzen 5 1400, where both CCX units on the die are enabled with 2 cores, each; and the L3 cache per CCX being chopped down to 4 MB; could be attributed to giving the four cores per active CCX a contiguous block of 8 MB L3 cache, to better cushion the NUMA local mode, in which certain applications' memory access can be localized to one die, for lower latency.

When AMD talks about a "diagonal configuration," it refers to the fact that two out of four 8-core "Zeppelin" dies physically present on the Threadripper multi-chip module, are disabled. The ones disabled are always diagonally opposite to each other. The Threadripper MCM is physically identical to the 32-core EPYC MCM, with four 8-core "Zeppelin" dies under its large integrated heatspreader (IHS); but due to platform-segmentation, and the fact that the Threadripper socket TR4 HEDT platform only has 4 memory channels (unlike 8 channels on the EPYC platform); two dies are completely disabled. The dies are disabled diagonally probably to spread heat better, or for better package wiring.
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63 Comments on AMD Ryzen Threadripper 1900X Core Configuration Detailed

#1
Prima.Vera
Sorry, so is basically a 16 Core CPU?
Posted on Reply
#2
Durvelle27
Prima.Vera said:
Sorry, so is basically a 16 Core CPU?
8C/16T
Posted on Reply
#3
Aquinus
Resident Wat-man
Prima.Vera said:
Sorry, so is basically a 16 Core CPU?
Durvelle27 said:
8C/16T
It's a 16 core CPU with 8 disabled cores. You get 2 of the 4 CCXs, 4 of the 8 DRAM channels, and likely half of the PCI-E lanes as well.
Posted on Reply
#4
Durvelle27
Aquinus said:
It's a 16 core CPU with 8 disabled cores. You get 2 of the 4 CCXs, 4 of the 8 DRAM channels, and likely half of the PCI-E lanes as well.
But it has Quad Channel RAM and the full 64 Lanes like all the other TRs
Posted on Reply
#5
phanbuey
Yeah this product doesn't make sense...
Posted on Reply
#6
NicklasAPJ
Prima.Vera said:
Sorry, so is basically a 16 Core CPU?
No is a 8 Core/HT CPU. the 2 others CPU dies, is just dummys.

So 2x Quad core.
Posted on Reply
#7
Aquinus
Resident Wat-man
I think I need patiently. :laugh:
Posted on Reply
#8
Fluffmeister
phanbuey said:
Yeah this product doesn't make sense...
For those that want a Ryzen 7, but with a bonkers-ly expensive motherboard. :P
Posted on Reply
#9
btarunr
Editor & Senior Moderator
Fluffmeister said:
For those that want a Ryzen 7, but with a bonkers-ly expensive motherboard. :p
You still get quad-channel memory, up to 2 TB memory support, ECC memory support, NVMe RAID, and 64-lane PCIe. But yes, according to AMD's own performance numbers, it's not much faster than an 1800X.
Posted on Reply
#11
Nihilus
Fluffmeister said:
For those that want a Ryzen 7, but with a bonkers-ly expensive motherboard. :p
It's for those that don't need extreme CPU power, but want extreme I/O capability.
Posted on Reply
#12
dwade
Nobody is even gonna buy this.
Posted on Reply
#13
phanbuey
Nihilus said:
It's for those that don't need extreme CPU power, but want extreme I/O capability.
with cryptomining usb devices and FPGAs i can completely see that... but still that many $$ with what is essentially the performance of an overclocked 1700 is a bit of a double take.

plus look at that schematic of it... that should make any environmentalist wince.

"Sir we have made a $549 cpu using slightly more than 3x the actual materials than necessary to achieve exactly the same performance as an overclocked $290 cpu made efficiently, which we have been making for some time."

"Excellent work, Balthor, name it threadripper and sell it in really extravagant packaging, make sure it has a somewhat unnecessary plastic guide that users can use to plop it into their gigantic lga sockets on their super expensive motherboards. Size matters, Balthor, users will see that."
Posted on Reply
#14
DeathtoGnomes
dwade said:
Nobody is even gonna buy this.
I will, eventually.
Posted on Reply
#15
de.das.dude
Pro Indian Modder
can we unlock the other CCX's like the good ol' phenom days?
Posted on Reply
#16
Camm
X399 is good until 2020. A 1900X wouldn't be a half bad buy to tide you over until a Zen2 CPU in 2018 tbh.
Posted on Reply
#17
Prima.Vera
Aquinus said:
It's a 16 core CPU with 8 disabled cores. You get 2 of the 4 CCXs, 4 of the 8 DRAM channels, and likely half of the PCI-E lanes as well.
Hmmm, so in theory one or more of the disabled Cores might(can) be unlocked using various techniques? ;)
Posted on Reply
#18
R0H1T
LogitechFan said:
I give you -- The Castrate!
Theon Greyjoy or the unsullied :rolleyes:
AMD quite literally removed a pair, ala Ramsay!
Posted on Reply
#19
Chaitanya
dwade said:
Nobody is even gonna buy this.
Those who didnt like PCI-E lane restriction of Ryzen 7 1800x will buy this CPU.
Posted on Reply
#20
de.das.dude
Pro Indian Modder
dwade said:
Nobody is even gonna buy this.
Sure it will. Lots of PCIE lanes for tons of IO options.

Plus this way AMD is effectively selling of dies that have less than ideal CCXs by blocking them off. It sure beats throwing them out in the bin.
Posted on Reply
#21
R0H1T
Prima.Vera said:
Hmmm, so in theory one or more of the disabled Cores might(can) be unlocked using various techniques? ;)
If they're not fused off, like Intel does it.
Posted on Reply
#22
Hokum
Threadripper "Miners edition" with 64 PCIE lanes that is a lot of Graphics card options...
Posted on Reply
#23
R-T-B
LogitechFan said:
I give you -- The Castrate!
Well I mean if cutting cores is castration, Intel must be some kind of... I'll let your imagination do the rest.
Posted on Reply
#24
Ferrum Master
R-T-B said:
Well I mean if cutting cores is castration, Intel must be some kind of... I'll let your imagination do the rest.
Well one.

Posted on Reply
#25
punani
R-T-B said:
Well I mean if cutting cores is castration, Intel must be some kind of... I'll let your imagination do the rest.
Latest still of Brian Krzanich

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