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Could AMD's Upcoming EPYC 'Rome' Server Processors Feature Up To 162 PCIe Lanes? (tomshardware.com)
jwhyche (Slashdot reader #6,192) tipped us off to some interesting speculation about AMD's upcoming Zen 2-based EPYC Rome server processors. "The new Epyc processor would be Gen 4 PCIe where Intel is still using Gen 3. Gen 4 PCIe features twice the bandwidth of the older Gen 3 specification."
And now Tom's Hardware reports: While AMD has said that a single EPYC Rome processor could deliver up to 128 PCIe lanes, the company hasn't stated how many lanes two processors could deliver in a dual-socket server. According to ServeTheHome.com, there's a distinct possibility EPYC could feature up to 162 PCIe 4.0 lanes in a dual-socket configuration, which is 82 more lanes than Intel's dual-socket Cascade Lake Xeon servers. That even beats Intel's latest 56-core 112-thread Platinum 9200-series processors, which expose 80 PCIe lanes per dual-socket server.
Patrick Kennedy at ServeTheHome, a publication focused on high-performance computing, and RetiredEngineer on Twitter have both concluded that two Rome CPUs could support 160 PCIe 4.0 lanes. Kennedy even expects there will be an additional PCIe lane per CPU (meaning 129 in a single socket), bringing the total number of lanes in a dual-socket server up to 162, but with the caveat that this additional lane per socket could only be used for the baseboard management controller (or BMC), a vital component of server motherboards... If @RetiredEngineer and ServeTheHome did their math correctly, then Intel has even more serious competition than AMD has let on.
And now Tom's Hardware reports: While AMD has said that a single EPYC Rome processor could deliver up to 128 PCIe lanes, the company hasn't stated how many lanes two processors could deliver in a dual-socket server. According to ServeTheHome.com, there's a distinct possibility EPYC could feature up to 162 PCIe 4.0 lanes in a dual-socket configuration, which is 82 more lanes than Intel's dual-socket Cascade Lake Xeon servers. That even beats Intel's latest 56-core 112-thread Platinum 9200-series processors, which expose 80 PCIe lanes per dual-socket server.
Patrick Kennedy at ServeTheHome, a publication focused on high-performance computing, and RetiredEngineer on Twitter have both concluded that two Rome CPUs could support 160 PCIe 4.0 lanes. Kennedy even expects there will be an additional PCIe lane per CPU (meaning 129 in a single socket), bringing the total number of lanes in a dual-socket server up to 162, but with the caveat that this additional lane per socket could only be used for the baseboard management controller (or BMC), a vital component of server motherboards... If @RetiredEngineer and ServeTheHome did their math correctly, then Intel has even more serious competition than AMD has let on.
I've been waiting for 3 years now for a relatively affordable desktop CPU with enough PCI Express Lanes.
My current CPU is an Intel i7 6800K, using the X99 motherboard chipset and it has 28 PCI Express Lanes. The 6850K has 40 PCI Express lanes but otherwise brings no performance increase. The next step in the upgrade process is the 6900K which, albeit on an EOL platform, has enough meat to satisfy my requirements... but costs a fortune. As a matter of fact, it costs as much if not more than a 2nd gen Threadripper (2920X), which has 12 cores and 24 threads available, compared to Intel's 8/16. But that requires changing the motherboard as well, and those are pricy too.
Only the HEDT CPUs have enough PCI Express Lanes, if you have 2x GPUs and a minimum of 2x nVME SSDs. There are regular desktop solutions which allow you to use such a hardware combo, but one GPU will run at 8X, the other at 4x, one SSD will run at 2X and the other would most likely use motherboard-provided PCI Express lanes, reducing the data throughput or providing variable performance. The 9900K from Intel has 16 PCI Express Lanes. The Ryzen 2700X has 16 lanes as well. You need more PCI Express lanes? Tough luck, cough up a couple grands on CPU+motherboard alone.
...gis sdrawkcab (usually not responding to ACs; don't bother posting as AC)