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You can also buy into TR4 Threadripper 1950x for ~$500 [0]. I'm using one to write this post. It's a great system and you can likely buy used for cheaper than $500. I'm also assuming this price will fall further once they announce another TR4 chip.

[0] - https://www.amazon.com/AMD-Threadripper-32-thread-Processor-...

I think the whole system price basically ends up as a wash with TR4 motherboards being at least ~$300 and needing a ~$100 cooler, I'm assuming these consumer chips will continue to have bundled coolers. The 3950X also draws 75W less than the 1950X so you can probably save a few bucks on the power supply and of course your electric bills over time.

The performance comparison will be interesting though. The 3950X should be quite a bit faster than the 1950X when it's not bottlenecked by memory bandwidth, but of course the 1950X still has twice the memory channels. Slightly offset by the Zen2 memory controller supporting higher frequency RAM. So which one is better will depend heavily on workload. I suspect that for a developer workstation the 3950X would be the better performer, most compilation workloads are not very sensitive to bandwidth.

Yea, the platform cost is higher. I ended up making a build you could make for ~$1,500 now. It was ~$1,600 when I made it. The biggest feature I'm interested in is the availability of PCIe lanes. I want this for adding a 10G nic later and two GPUs at some point as well (host & guest).

If you don't need those features you're completely correct about the 3950x.

Ah, GPU passthrough?

My biggest problem with virtualization is USB. I have a libvirt with GPU passthrough setup that works great, but have been unable to get a USB controller of any sort to passthrough; always winds up in a group with a bunch of other PCI-e devices. And ordinary forwarding with SPICE or something isn’t really sufficient for what I’d like to set up...

It's technically a security risk, but take a look at the acs patch that's out there. It'll forcefully split up the iommu groups to the hypervisor so you can do the pass through, but it does mean that the cards that were in the same group before can technically see each other's dma and other stuff on the bus. For anything other than a shared host it's pretty much fine though.

Have you tried IOMMU splitting? https://forums.unraid.net/topic/72027-iommu-group-splitting-...

(disclaimer - I don't own a board that can do this, I will one day, though).

I have, though it causes a lot of stability problems :(

This should be doable on desktop Ryzen. I currently have one GPU (x16) + NVMe SSD (x4) + 10G NIC (x4 from chipset). The 16x can be split x8/x8 for dual GPU.

https://linustechtips.com/main/topic/799836-pcie-lanes-for-r... — nice diagram of lanes

If you're running 10G through the chipset and running GPUs on a x8 config you're going to bottleneck yourself in my opinion.

My single port Intel X520 achieves line rate through x4 chipset lanes just fine.

GPUs generally don't come close to saturating x8 3.0 lanes, unless you have a very specific workload (like the new 3dmark bandwidth benchmark AMD used to demo PCIe 4.0).

Games don't do nearly enough asset streaming to use a lot of bandwidth, since the amount of assets used at the same time is limited by VRAM size, and most stuff is kept around for quite some time. Offline 3D renderers like Blender Cycles IIRC just upload the whole scene at once and then path tracing happens in VRAM without much I/O. For buttcoin mining, people literally use boards with tons of x1 slots + risers. No idea how neural nets behave, but would make sense that they also just keep updating the weights in VRAM.

Except this is pcie 4 vs pcie 3 so it's double the lanes for the latter, so no, x8 pcie 4 will not bottleneck anything. Unfortunately GPU do not support pcie 4 yet, but it's not a problem for integrated 10GbE.

I thought AMD said their. New card was pcie 4

Yes, the Navi card of course supports gen4, and even the Vega20 did too. At least in the original Instinct variant (most places on the internet say that gen4 was cut on the consumer Radeon VII card)

I do wonder if they'll continue with Threadripper. If it exists in the next generation, it might simply be as rebadged and slightly nerfed EPYC chips rather than something custom.

AMD has already stated that they're going to continue with Threadripper.

It would leave a fairly big gap in the lineup with nothing to compete against Intel's X299 platform. AM4 is lacking in memory channels and PCIe lanes. Epyc has much lower clockspeeds, much more expensive CPUs, and more expensive motherboards than Threadripper.

> it might simply be as rebadged and slightly nerfed EPYC chips

Well, that is what first-gen Threadripper was. Same socket and all, but with half the connected DDR lanes and a pin telling the motherboard it's not EPYC.

The first-gen Threadripper only had two dies, and even the WX series was a bit weird internally, with two of the four dies not being able to perform IO.

I know it's not a big difference, but given the changes to IO and the 16 core consumer version, I don't see why there would be any internal difference to EPYC this time around (which this article claims will have a variable number of chiplets).

The only difference would be the number of DDR channels I guess, yeah.

I hope as well; moreover, I hope they'd release a 64 core TR next year that could last a decade (even if it costs 2,500+). There are rumors Zen 3 should bring 4-way SMP, i.e. 4 threads/core instead of 2, so that might lead to ridiculous numbers of threads in normal systems.

As Lisa said, TRs were distinct to Epycs; I guess using UDIMMs vs RDIMMs and much higher base clock (except for the high freq EPYC 7371) led to a few changes.

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