AMD EPYC 7C13 Is a Surprisingly Cheap and Good CPU

https://www.servethehome.com/amd-epyc-7c13-is-a-surprisingly-cheap-and-good-cpu/

by PaulHoule • 2 years ago

170 75 2 years ago

jeffbee4• 2 years ago

This is some fell-off-a-truck stuff. Aren't the weird part numbers with infix letters custom made for large customers (Amazon, Google, et al.)?

astrodust• 2 years ago

Large cloud providers dump their gear in bulk all the time, and these parts get picked, tested and packaged for resale.

I'm not sure these custom parts are barred from resale like the "ES" (Engineering Sample) type chips are.

jeffbee4• 2 years ago

I don't think they are barred from sale, but I do think that if you're selling secondhand CPUs on Newegg, the used nature of the hardware should be prominently stated. That is, for customers who are still willing to risk their money on Newegg.

With those caveats it's a great deal for something like a build box. You could put this into an existing ATX case with $1000 worth of RAM (that you may already own?) for less than the price of a new Threadripper CPU.

kjs3• 2 years ago

They don't have to be used; there's overstock and grey market possibilities.

I've seen many times (usually smaller) runs of products and noticed house-marked or otherwise oddly identified chips and when asked the producer said "the OEM didn't use them so they sold them to us cheap". And I've certainly bought a couple brand new big-box labeled motherboards that were really (and obviously) minor variations of existing Asus, Gigabyte or Supermicro motherboards. Shoot, somewhere I've got a NiB Intel Phi card with a weird part number only because it was made for (I think) Dell and now that Phi is dead they were being fire-saled.

pengaru• 2 years ago

Or whole-system vendors like Lenovo/HP?

JonChesterfield• 2 years ago

Nah, it's just variation on price of older stock. Relatively few buyers and relatively low stock pushes the variance up. E.g. I see a 7763 listed at 3k in one store and 4k in another.

If you can find a motherboard to match it's a lot of computer for the price.

derefr2• 2 years ago

Some maybe-interesting observations about my experiences over the last few years, as someone who uses both cloud-provisioned (GCP N2D) and dedicated-server (e.g. OVH HGR-HCI-class) AMD EPYC-based machines at $work.

• GCP N2D instances always had a strict per-AZ allocation quota. This allocation quota has not increased over time. And when we asked to have it bumped up, it was the only time a quota-increase request of ours has ever been denied.

• When OVH was offering their HGR-HCI-6 machine type (2x EPYC 7532), we provisioned a few of them. The first few, leased ~2 years back, each took a few days to provision — presumably, OVH doesn't buy these expensive CPUs until a customer asks for a machine to be stood up with one in them. More recently, though (~6mo ago), for the same machine type, they gave us a provisioning lead time of more than a month, due to supply difficulties for the CPU.

• These chips were buggy! Again on OVH, when allocating these HGR-HCI-6 machines, we were allocated two separate machines that ended up having CPU faults. (Symptoms: random reboots after an hour or two of heavily utilizing the native AES-NI instructions; and spurious "PCI-e link training errors" in talking to the network card and/or NVMe drives.) They were replaced quickly, but I've never seen this kind of CPU fault on a hardware-managed system before or since.

• Just a month ago, the high-end dedicated-server hosters (OVH, but also Hetzner and so forth) seem to have removed all their SKUs that use 2nd- and 3rd-gen EPYC 7xxx CPUs. (Except for one baseline SKU on OVH, which is probably there because they have a big pile of them.) Everything suddenly switched over to 4th-gen 9xxx EPYCs just a month or two ago. It might just be that availability of these 9xxx EPYCs is finally reaching levels where these providers think they can meet demand with them — but everyone switching over simultaneously, and dropping their old SKUs at the same time?

• GCP recently launched the storage-optimized Z3 instance type. They chose to build this instance type on an Intel platform (Sapphire Rapids.) That's even though AMD EPYCs have had enough PCIe lanes to deliver equivalent performance to this Z3 platform — ignoring the "Titanium offload" part, which isn't CPU-platform-specific — for years. (In fact, the need for a huge pool of fast NVMe is in part why we switched some of our base load from GCP over to those OVH HGR-HCI-6 instances — which satisfied our needs quite well.) GCP could in theory have launched something akin to this instance type, with the same 36TiB storage pool size (but PCIe 4.0 speeds rather than 5.0) three years ago, using EPYC 7xxxs. Cusomers have been asking for something like that for years now — wondering why GCP instances are all limited to 8.8TiB of local NVMe. (We actually asked them ourselves, back then, where "the instance type with more local NVMe" was. They gave a very handwave-y response, which in retrospect, may have been a "we're trying, but it's not looking good for delivering this at scale right now" response.)

These points all lead me to believe that something weird happened with the EPYC 7xxx rollout. Supply didn't grow to meet demand over time.

And then, suddenly, after the seeming EOL of these chips — but long before cloud providers would normally cycle them out — we're seeing 7xxxs ending up on the open market, in enough bulk to make them affordable? Bizarre.

---

My own vague hypothesis at this point, is that at some point during the generation, AMD discovered a fatal flaw in the silicon of the entire EPYC 7xxx platform. Maybe it was the hardware crypto instructions, like I saw. Or maybe it was some capability more specific to cloud-computing customers (SEV-SNP?) that turned out to not work right (which would make more sense given that Threadrippers didn't see the same problems.) So the big cloud customers immediately halted their purchase orders (keeping only what they had already installed so as to not disturb existing customer workloads); and AMD responded by scaling down production.

This resulted in two things: a supply shock of AMD EPYC-based machines/VMs that lasted for a while; but also, negotiated settlements with the cloud vendors, where AMD was now obligated to fulfill existing POs for 7xxx parts with 9xxxs, as they ramped up production of those. Which is why 9xxxs have taken so long (2 years!) to make it onto the open market: the lines have been dedicated to fulfilling not just 9xxx bulk purchase-orders, but also 7xxx purchase-orders.

(And which is why the switchover to 9xxx among smaller players is so immediate: such a switchover has been on every hosting company's roadmap for a long time now, having been repeatedly delayed by supply issues due to the huge volume of 9xxx parts required to satisfy the clouds' backlogged demand. They've had a stock of 9xxx-compatible motherboards + memory + PSUs + chassis just sitting there for months/years now, waiting for 9xxx CPUs to slot into them.)

Perhaps we're seeing these cloud-customer 7Cxx parts on the open market now, because the clouds have finally received enough 9xxxs to satisfy their actual demand for 9xxxs, and their backlogged demand for 7xxxs; and the clouds are now finally at the point where they can replace their initial actual (faulty / feature-disabled) 7xxx parts they were sent with 9xxxs, selling off the 7xxx parts.

My guess is that, now that they have "fixed" AMD chips in place, we'll soon see the cloud providers heavily hyping up some particular AMD-silicon-enabled feature that they had been starting to market four years ago, but then went radio-silent on. ("Confidential computing", maybe.)

---

I'd love to hear what someone with more insider knowledge thinks is happening here.

AnthonyMouse2• 2 years ago

CPU faults on individual machines aren't that rare. The machine has a dodgy power supply that almost works but has voltage drop under load etc. Sometimes this can be caused by environmental factors. The rack is positioned poorly and has thermal issues, the UPS is supplying bad power etc. Then you can see issues with multiple machines, or replace the machine without fixing the issue. Vendors often put machines for the same customer in the same rack for various reasons, e.g. because they might send a lot of traffic to each other and put less load on their network if connected to the same switch, but then if there is a problem in that rack it affects more of your machines.

The Epyc 7000 series was popular. There have been enough of them in private hands for long enough that if there were widespread issues they would be well-known.

It's possible that AMD didn't order enough capacity from TSMC to meet demand, and couldn't get more during the COVID supply chain issues. For the 9000 series they learned from their mistake, or there is otherwise more fab capacity available now, so customers can get them. Meanwhile cloud providers really like Zen4c because they can sell "cores" that cost less and use less power, so they're buying it and replacing their existing hardware as they tend to do regardless. That is typically how they expand their business: If you add more servers you need more real estate and power and cooling. If you replace older servers with faster ones, you don't.

486sx332• 2 years ago

NOT shipped by newegg but very interesting https://www.newegg.com/tyan-s8030gm4ne-2t-supports-amd-epyc-...

Seems like a good value per dollar for a monero mining rig approx 4 x the performance of a 5950x on monerobenchmark site. Given that the epyc has about 4 times the cache (256MB vs 64MB) this makes sense in the monero world. I'd assume real world performance side by side compairison the epyc would get up past 4x than a real world 5950x which requires a lot of tweaking to get anywhere close the monerobenchmark numbers.. I'd expect the epyc runs better out of the box

bethekind2• 2 years ago

I've always wondered how the epycs with huge amounts of L3 would perform on monero.

Is there an optimal core to l3 ratio? Or is it always more is better

486sx332• 2 years ago

here is a quick blurb from someone on reddit which sums up the general advice in a way that matches my experience

"most mining algorithms targeted for CPUs require certain amount of L3 cache per thread (core), usually 1-4MB, so just divide your total amount of CPU L3 cache by this number and the result is how many threads can you run max on your cpu. For example if an algorithm requires 2MB of cache per thread and you have a 10-core 16MB L3 cache cpu, you can run at most 16/2=8 threads, 9 or 10 threads will result in worse performance as cores will be kicking out each other's data from the cache. " https://www.reddit.com/r/MoneroMining/comments/jurv6j/proces...

Below are two real world examples of monero mining I run myself

An example is my i9-10850K. exact same performance using 8 cores or 10 cores (16 threads or 20 threads).. in fact it slightly goes down performance wise at 20 threads.. Given that it has 20MB cache, it is an example of the bottom limit not being optimal. using this example i'd say minimum is around 1.12MB per thread, or 2.25MB per core

Another machine I have, the 5950x crunches away all day and night using all threads (32) on all cores (16) with 64MB cache no problem this correlates to 4MB per core / 2MB per thread.. and it seems like more than what it needs because I can use the machine all day for daily tasks with no hiccups and while mining full out. If you have a desktop at work and need to kill it all day long, the 5950x will absolutely take anything and everything you throw at it.. samsung b-die ram helps monero mining as well. I run only 32GB but in 4 8GB b-die sticks.

pclmulqdq• 2 years ago

I think ~2 MB (a bit more) is that ratio, at least as designed. It's possible that you can hyperthread Monero with 4-5 MB of cache per core.

Patrick-STH4• 2 years ago

We bought Newegg out of all the new Tyan systems they had in stock. I was hoping to do a piece on them, but they must have had few in inventory

mise_en_place• 2 years ago

It's good but I have a feeling anything you find on aftermarket will be used and abused. These chips are designed to handle high thermal load, but if it's been in a DC or server room, it may impact its longevity.

wmf3• 2 years ago

"Abused" chips are mostly a myth and Milan is not that old so these chips should have plenty of life left in them.

londons_explore2• 2 years ago

Agreed - with CPU's, if it's working the day you buy it, it will most likely still be working in 10 years with typical desktop use cases, no matter the past life it had.

irusensei• 2 years ago

It kinda feels like the mining GPU being bad myth when in fact miners nursed those GPUs like babies because their income depended on those devices.

usefulcat• 2 years ago

I'd much rather have something that came from a server room. Lots of cool, dust-free air--far better than a machine that's been sitting under someone's desk, clogged with dust and exposed to who know what temperatures.

jmole• 2 years ago

I recently picked up a 64-core AMD EPYC Genoa QS (eng sample) on ebay for $1600, and have been very pleased with the performance.

mhuffman• 2 years ago

Agreed! I have a AMD EPYC 7702P in an ASRocks mb and have been very pleased with performance in a homelab.

naked-ferret• 2 years ago

What app are they using in this screenshot? https://www.servethehome.com/amd-epyc-7c13-is-a-surprisingly...

Looks very neat!

qwertox• 2 years ago

s-tui: https://github.com/amanusk/s-tui

jeffbee4• 2 years ago

The advantage of this program is the graphical presentation, but it's giving a fraction of the information offered by "turbostat" while using > 10x more CPU time.

tamimio• 2 years ago

I don’t know exactly but I personally use Btop yo monitor resources https://github.com/aristocratos/btop

MenhirMike4• 2 years ago

Still rocking my EPYC 7282 in my home server, which really sits in a sweet spots: 16 Cores, about $700, 120W TDP (because of the reduced memory bandwidth).

Looks like the 7303 fills that same niche in the Milan generation (and should be compatible with any ROME mainboard, possibly after a BIOS update), or if you're building a new system you can get the 32-Core Siena 8324PN for about 130W TDP.

(While it may be silly to look at TDP for a server CPU, it does matter for home servers if you want a regular PC Chassis and not a 1U/2U case with a 12W Delta cooling fan that is audible three cities over. In fact, you can get the 8-Core 80W 8324PN and still get all those nice PCIe lanes to connect NVMe SSDs to, and of course ECC RAM that doesn't require hunting down a specific motherboard and hoping for the best.)

semi-extrinsic• 2 years ago

With these constraints, what is the benefit of Epyc over Threadripper? I've been running a 3970x in my workstation for several years now. Sure it's about twice the TDP, but with water cooling it stays quite silent even on full load.

MenhirMike4• 2 years ago

I wanted remote management (IPMI), which none of the Threadripper boards offered. I went with the ASRock Rack ROMED8-2T, which also has 2x 10G Ethernet on board, which was another nice thing I didn't have to sacrifice a PCIe slot for. It does require a Tower Case with space for fans on top though, because the CPU slot is rotated 90 Degrees compared to Threadripper boards, so the airflow is different.

The EPYC CPU was also a quite a bit cheaper than the then-equivalent Threadripper 2950X (though the mainboard being $600 made up for that). This is even more true today because AMD really jacked up the prices for Threadripper to the point that EPYC is actually a good budget alternative. I guess that making 16 Core Ryzen made low-end Threadrippers less attractive, but it's the PCIe slots that were so great about those!

Also, I do believe that it was much easier to find 64 GB RDIMMs whereas 64 GB ECC UDIMMs were not available or much more expensive, though my memory (ha!) is hazy on that, I just remember it being a PITA.

So that EPYC system was just much more compelling.

z8• 2 years ago

It should be noted that non-vendorlocked 7282s can be had for as little as 80 bucks on eBay. Bought one just a few weeks ago. Lovely piece of silicon.

gigatexal• 2 years ago

What issues come with the vendor locking?

justinclift• 2 years ago

Saw them, but the motherboards they work in are still sky high pricing. :(

tiffanyh• 2 years ago

Last Generation

Am I mistaken but isn't this AMD's last generation server proc?

The current generation is 7xx4 / 9xx4.

Which should be surprising it's cheaper.

wmf3• 2 years ago

Yes, it's the previous generation. Homelabbers mostly buy older used equipment at deep discounts.

Patrick-STH4• 2 years ago

There is not an EPYC 7xx4. EPYC 8004 is Siena. We reviewed an ASRock Rack Siena platform this week actually.

We had this in the Genoa launch piece but AMD largely kept $/core constant between Milan and Genoa. Milan is still being sold since it uses cheaper PCIe Gen4 motherboards and DDR4.

On the server side it takes a few quarters for new products to start making up the majority of shipments. These days it is better to think of new servers as N, N-1, and still some N-2 generations being sold as new.

dheera• 2 years ago

This naming is confusing. Is 7C13 > 7950X? Why can't companies stick to simple conventions of "higher numbers are better" ...

Even NVIDIA ... A800 > A100 > A10 but A6000 < A100

Osiris• 2 years ago

Completely different platform. The Ryzen 7950X is a consumer CPU. The 7C13 is a server CPU and follows a separate naming convention.

It shouldn’t be confusing because you really wouldn’t be comparing them to each other.

mrb2• 2 years ago

The article states the 7C13, priced in the $1900-2000 range, seems to be a low-cost version of the more common retail 7713P, priced officially around $5000 about 2-3 years ago. But the thing is the 7713P itself is such an old processor that it can be found for even cheaper: from $1300 to $2000 right now.

https://www.ebay.com/sch/i.html?_from=R40&_nkw=amd+7713P&_sa...

https://www.amazon.com/dp/B0BRR2369B (listed by small third-party vendor)

https://starmicroinc.net/amd-epyc-7713p-2-0ghz-socket-sp3-64...

Of course these are sellers who sell low volumes and who are not well-known, but that's just because all these processors, 7C13 or 7713P, are at their end-of-life so none of the big retailers have them in stock.

metadat3• 2 years ago

Nice find.

What are the practical differences between EPYC 7713P and 7C13, if any?

If there aren't any, that's an oversight by STH. I wonder where they got this scoop.

Patrick-STH4• 2 years ago

Easy one would be the P part is single socket only.

I was browsing one day looking for barebones to throw in one of our clusters and saw Newegg was selling these 1U servers cheap ($2200-2300)

Usually with AMD desktop and server CPUs buying high core counts at lower TDP yields a great perf/ W figure

chipdart• 2 years ago

But the thing is the 7713P itself is such an old processor that it can be found for even cheaper

If you're pointing out used hardware, doesn't it make sense to factor in service life?

Google tells me that the service life of a processor can be as low as 5 years it it's subjected to poor cooling, and certainly those who are getting rid of those expensive processors are doing so due to a need to rotate their hardware.

underlogic• 2 years ago

have a 7B13 gathering dust if anyone is in the market in the bay

1letterunixname• 2 years ago

I bought 2 new retail boxed WOF 7402's in 2020 for $734.54 USD each. 96 threads and 256 MiB L3 total, decent single- and multi-core performance. So I can't currently justify upgrading to (used) 7742/7702/7H12, much less any form of Milan or later chips. I also looked into upgrading to 1, 2, or 4 TiB of RAM, but the costs still remain absurd.

I guess I'll take my type-1 virtualized, 2 Romes, 0.5 TiB DDR4-3200 RDRAM, 32 TiB NVMe SSDs, and ~150 TiB net RAID10 of Ultrastar HDD until the wheels fall off, because it's more than I'll need for almost any purpose. Whenever I need more temporarily, I rent it rather than sink personal $ into excess metal.

PS: During the pandemicfest, I shoehorned the H11DSi-NT into a Core V71 TGE with a bit of Dremeling and tapping holes. The case is rammed with enormous Noctua fans, an AX1600i PSU, and USB distribution for a TRNG and an HSM.

rakejake• 2 years ago

May I ask what you use the machine for?

pm2222• 2 years ago

For home use I'd rather get 7945hx only issue is 96G ram.

https://store.minisforum.com/products/minisforum-bd770i

metadat3• 2 years ago

That's a nice form factor, but the lack of 10g ethernet or a PCIe slot is unfortunate.

fransje262• 2 years ago

Isn't item (5) a full-size PCIe 5.0 x16 slot?

fransje262• 2 years ago

Looks interesting. But a genuine question. What is the benefit/appeal over a standard mini-ATX board using a desktop-line AMD processor?

AMD EPYC 7C13 Is a Surprisingly Cheap and Good CPU

Related Stories