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Threadripper 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 TR
by LeifCarrotson 8y ago
Threadripper 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.
- wbl 8y agoDepends on the arithmetic intensity. Higher intensity means less memory bandwidth needed to keep the cores happily crunching.
- floatboth 8y ago> enormous 4094-pin TR4 socket A lot of these pins aren't used on TR, since you only get half the memory controllers you'd have with EPYC
- LeifCarrotson 8y agoThat's true. A staggering number of them are power delivery to start with - you don't waste anywhere near half the socket by dropping 4 memory controllers (!) but yeah, it's not EPYC.
- elihu 8y agoFor what it's worth, Broadwell E5v4 Xeons (which have been out a little over 2 years) use a 2011-3 socket and support DDR4-2400.