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Can anybody fill me in on why people these days are spending almost the same money for a last-gen, medium-high end, 12 core, 24 thread CPU and a motherboard? Wh

by flatb 8y ago

Can anybody fill me in on why people these days are spending almost the same money for a last-gen, medium-high end, 12 core, 24 thread CPU and a motherboard? What features would an almost $400 motherboard have that could justify that price?

walshemj 8y ago
The thread ripper chip sets x399 are expensive and also if you want to put 4x GPU's not all MB support this and the power required to run this all. Baring in mind spending $400 on a mb pales when you are taking about a $1800 dollar CPU and 4x high end graphic's cards
paulmd 8y ago
Threadripper is actually not even that great here, it's NUMA (half of the lanes are attached to each die) and if you just want NUMA you can do a dual-socket E5-2650 system for like half the price. Same logic applies to TR here: https://www.servethehome.com/how-intel-skylake-sp-changes-impacted-single-root-pcie-deep-learning-servers/ https://www.servethehome.com/how-intel-skylake-sp-changes-im... You're not using the CPU for anything, there is no reason to have a beefy 12-core CPU there. If you really want Threadripper, the 8-core version is fine. Again, personally I'd look at X79 boards, since they are pretty cheap and you can do up to 4 GPUs off a single root, depending on the board. There are new-production boards available from China on eBay, see ex: "Runing X79Z". Figure about $150 for the mobo, about $100 for the processor, and then you can stack in up to 128 GB of RAM, including ECC RDIMMs, which runs about $50 per 16 GB. There are some Z170/Z270 boards like the "Supercarrier" from Asrock that include PLX chips to multiplex your x16 lanes up to 4 16x slots (does not increase bandwidth, just allows more GPUs to share it at full speed!). They also will not support ECC (you need a C-series chipset for that, which run >$200). So far most OEMs have been avoiding putting out high-end boards for Z370 because they know Z390 is right around the corner so there is currently no SuperCarrier available for the 8000 series.

by flatb 8y ago

walshemj 8y ago

The thread ripper chip sets x399 are expensive and also if you want to put 4x GPU's not all MB support this and the power required to run this all. Baring in mind spending $400 on a mb pales when you are taking about a $1800 dollar CPU and 4x high end graphic's cards

paulmd 8y ago

Threadripper is actually not even that great here, it's NUMA (half of the lanes are attached to each die) and if you just want NUMA you can do a dual-socket E5-2650 system for like half the price. Same logic applies to TR here: https://www.servethehome.com/how-intel-skylake-sp-changes-impacted-single-root-pcie-deep-learning-servers/ https://www.servethehome.com/how-intel-skylake-sp-changes-im... You're not using the CPU for anything, there is no reason to have a beefy 12-core CPU there. If you really want Threadripper, the 8-core version is fine. Again, personally I'd look at X79 boards, since they are pretty cheap and you can do up to 4 GPUs off a single root, depending on the board. There are new-production boards available from China on eBay, see ex: "Runing X79Z". Figure about $150 for the mobo, about $100 for the processor, and then you can stack in up to 128 GB of RAM, including ECC RDIMMs, which runs about $50 per 16 GB. There are some Z170/Z270 boards like the "Supercarrier" from Asrock that include PLX chips to multiplex your x16 lanes up to 4 16x slots (does not increase bandwidth, just allows more GPUs to share it at full speed!). They also will not support ECC (you need a C-series chipset for that, which run >$200). So far most OEMs have been avoiding putting out high-end boards for Z370 because they know Z390 is right around the corner so there is currently no SuperCarrier available for the 8000 series.