4 ms·
Bloody hell, this processor has more cores than the dual socket Xeon HPCs that my lab bought 2 years ago. Amazing. Honest question: Isn't the memory throughput
by whatever1 8y ago
Bloody hell, this processor has more cores than the dual socket Xeon HPCs that my lab bought 2 years ago. Amazing.
Honest question: Isn't the memory throughput an issue when you try to feed 32 hungry processors?
- adreamingsoul 8y agoYes, hopefully the motherboard manufactures take that seriously.
- Symmetry 8y agoWell, it's got four fairly fast memory channels but yes, you'll probably tend to be more memory limited with this guy - though the 64 MB of L3 should help in many cases.
- valarauca1 8y agoFor TR kind of. In the newer models only half the cores have direct access to a DDR channel. This shows in memory bounded benchmarks, but Epyc (server line) elevates this problem by have 8 (!!) memory channels, instead of the consumer TR’s 4. Ultimately it depends on how cache friendly your workload is. The 32c/64t is kind of a marketting gimmick selling binned Eypcs. If your doing memory bound HPC consider the 16c/32t model for roughly equal performance at a lower price.
- CitizenKane 8y agoIt's the unfortunate downside to these. Two of the dies don't have direct access to memory, but it seems like AMD didn't want to do a refresh of the pinouts and force socket updates. I suspect this will be left for the Zen 2 version of Threadripper. That being said, I imagine in most circumstances the performance should still be pretty good.
- LeifCarrotson 8y agoThreadripper uses quad-channel DDR4-2666 memory. That gets you 80 GB/s memory bandwidth, which is possible because the processor sits in an enormous 4094-pin TR4 socket. Your Xeons were probably in 2011 pin sockets with DDR3-1866 resulting in 70 GB/s memory bandwidth. One Threadripper has more than double the pin count and slightly more total memory bandwidth than your dual Xeon machine. Also, your the Intel setup has a 25 GB/s QPI bus between the processors. Threadripper runs an Infinity Fabric bus, with 42 GB/s between each die internally (aggregate 170 GB/s). While a couple of those internal dies are not directly connected to the memory, you should have little trouble sharing meals among those hungry processors.
- aeleos 8y agoActually with this release threadripper 2 will support DDR4-2933 which should increase the memory bandwith and the throughput of the infinity fabric if I'm not mistaken (I am pretty sure infinity fabric runs at the ram speed)
- dragontamer 8y agoMost people overclock RAM using XMP settings and hit 3200 MT/s easily (which also overclocks the infinity fabric). I've seen some people hit 3466MT/s on higher-end more expensive RAM on AMD's 12nm stuffs (Ryzen 2). So that's probably the practical limit. 3200 MT/s on Hynix dies is probably a reasonable expectation.
- stingraycharles 8y agoDo you know whether Threadripper is affected by NUMA issues? Otherwise this could be an additional selling point for applications that need a lot of memory (e.g. databases, where you do not want the memory latency to be unpredictable depending upon which socket you are running on)
- nimish 8y agoIt is. Only 1/2 of the dies are connected directly to memory controllers. For actual production workloads you want EPYC which has a memory controller for each die, meaning it's 8 channel.