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AMD Discloses Initial Zen 2 Details

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Re: AMD Discloses Initial Zen 2 Details

#21

Post by s3cur3 »

5436436347 wrote: post #17
s3cur3 wrote: post #14

Earlier quoted context omitted.

Benchmarks on the 32-core TR are... disappointing, to say the least.[1] If you’re purely compute bound, it can be a win over the 16-core version, but if memory access is a factor, it’s a wash due to the extra hops to memory. And to my mind, there are very few pure-compute applications that wouldn’t benefit more from AVX2 and the like... in which case a cheaper Intel CPU would still wipe the floor with the 32-core chi…

Those (Anandtech) benchmarks were performed on Windows. All threadripper benchmarks on Linux show that it is nowhere near as awful a performer as on Windows and most compute workloads do scale okay. Seen multiple ideas thrown around like Windows not being NUMA aware with this processor or just plain bad core scheduling

They did a follow up changing the scheduling policy for thread 0 (again, still on Windows) and it didn’t make a difference for almost all their workloads: https://www.anandtech.com/show/13446/the-quiz-on-cpu-0-playi...

Re: AMD Discloses Initial Zen 2 Details

#22

Post by blattimwind »

snuxoll wrote: post #18
tolien wrote: post #6

Earlier quoted context omitted.

Sort of - they let mainboard vendors decide whether to support it or not, which means it can be a crapshoot. For example, MSI's been known in the past to kill ECC support with a BIOS update; some vendors have tested that you can use ECC RAM but won't enable any of the error correction (for example, Gigabyte say this in [1]: "non-ECC mode".) Selfishly I really wish they would make it easier, because I'm in the market…

If you’re wanting a storage box usually it’s just less headache to buy used server gear off eBay. Plenty of bays, DDR3 RDIMM’s are cheap, and power efficient ivy/sandy bridge systems are finally in affordable price ranges. I’m the kind of person that lurks in /r/homelab though - so I’ve also got a 25U rack to keep all my gear. If you want a tower to stuff in a corner things get more dicey.

2011-1 systems really aren't that power efficient. 16 DIMMs, 2 sockets will draw ~120 W idle.

Re: AMD Discloses Initial Zen 2 Details

#23

Post by walrus01 »

s3cur3 wrote: post #14
bhouston wrote: post #7

64 cores with 128 threads. Hope that comes to threadripper. I love and for bringing back competition to the CPU market. We've bought a ton of amd machines in the last year, great bargains in our space.

Benchmarks on the 32-core TR are... disappointing, to say the least.[1] If you’re purely compute bound, it can be a win over the 16-core version, but if memory access is a factor, it’s a wash due to the extra hops to memory. And to my mind, there are very few pure-compute applications that wouldn’t benefit more from AVX2 and the like... in which case a cheaper Intel CPU would still wipe the floor with the 32-core chi…

It is not just about 32-core compute performance, if you compare a $385 threadripper motherboard + $650 CPU to the equivalent Intel competition, for single socket, the Threadripper is far ahead in terms of high bandwidth I/O. The threadripper has 64 PCI-Express 3.0 lanes direct to the CPU, for use with things like 25/40/100GbE network interfaces, or very large numbers of 10GbE interfaces. Or low-latency cluster interconnect fabric cards.

Re: AMD Discloses Initial Zen 2 Details

#29

Post by bluecalm »

blattimwind wrote: post #20
anticensor wrote: post #19

Earlier quoted context omitted.

Just run 2 Windows instances. Problem solved.

Windows can use more than 64 hardware threads, but a single process kinda can't.

It can but you have to take care too change process affinity groups every time you want to work with threads in another group as a group is limited to 64 virtual cores. It complicates thread pool implementation significantly.

Re: AMD Discloses Initial Zen 2 Details

#30

Post by mda »

s3cur3 wrote: post #21
5436436347 wrote: post #17

Earlier quoted context omitted.

Those (Anandtech) benchmarks were performed on Windows. All threadripper benchmarks on Linux show that it is nowhere near as awful a performer as on Windows and most compute workloads do scale okay. Seen multiple ideas thrown around like Windows not being NUMA aware with this processor or just plain bad core scheduling

They did a follow up changing the scheduling policy for thread 0 (again, still on Windows) and it didn’t make a difference for almost all their workloads: https://www.anandtech.com/show/13446/the-quiz-on-cpu-0-playi...

See the phoronix benchmarks, linux performs much better on same workloads.
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