Is this a good deal?

[Millennium]

Hi there

I'm looking to get a box or two (max threads / mem) for CPU mining towards the end of the year. I'll need some time to set it up, and probably sell it on after 2-3 months. This depends on how quickly the difficulty ramps up.

Here is what I'm thinking: ebay link

Dell PowerEdge C6100 8x Xeon Quad Core 32GB RAM Node Server it's a 4 node 2u chassis.

I will try and run off USB or TCP/IP boot and won't need any caddies, hd, ssd, or rails (or at least that's the plan?).

I will need to run virtual machines, probably 2 cores per VM, Linux probably too.

Do you think this is good value? It's only 2.13ghz per core, but it's sandy/ivy era tech, so it's not too shabby. 1gb per core will hopefully be just enough. I'm also considering upping the spec of the CPUs to something with hyperthreading if it's cheap enough to make sense.

thanks

[scaryjim]

... It's only 2.13ghz per core, but it's sandy/ivy era tech, so it's not too shabby. ...

In fact it's Nehalem - first generation Core i in socket 1366. I doubt it'd be even vaguely cheap to try to upgrade to HT-enabled 2P processors within an 80W TDP. It also means that the IPC is well short of any modern processor (sandy bridge and Haswell had reasonable IPC increases alongside higher clock speeds at a given TDP).

That said ...

Is it good value? Well, assuming that you get everything they list at the price it states (£195 for the base config) and it all works, then yes, it's ridiculous value - each 8 core/8GB RAM node is coming in at ~ £50. TBH I'd be inclined to chuck in the full 12 drive caddies too, given it only adds £80 to the total selling price. It's a lot of compute power for the money.

Is it a good buy? Well ... I'd personally be worried about the heat and power draw. 8x 80W TDP CPUs in one chassis is a lot of heat to dissipate, and a lot of power to supply (potentially 640W just for the CPUs, then power for the chipset and motherboard - no wonder it has a >1k power supply). When trying to come up with a comparison my thoughts (naturally) turned to Ryzen, which has amazing MT energy efficiency.

And here's where things got interesting. Having tracked down some IPC comparisons between Haswell and Nehalem (Ryzen is generally accepted to have ~ Haswell IPC), I was surprised that my rule of thumb calculation - assuming linear scaling across cores, clock speed and IPC - suggested that a single Ryzen 7 1700 PC would have over 90% of the performance of the entire server, while consuming around 1/10th as much electricity.

By my rough calculations, you'd spend over £500 less on electricity per year running a basic Ryzen 7 PC 24/7 than running the 8 node Xeon server. Planning on running it for ~ 2 years? That's over £1000 more in electric.

So, honestly, while the server is technically good value, I don't think it's a worthwhile purchase for cryptocurrency mining - the running costs are just going to be way too high...

[Splash]

quite a lot of the vExpert folks used to run these for VMware home labs once they'd filled them with RAM. Nowadays it's all about the NUCs or the newer Supermicro boxes - these things are hella noisy, and as Jim says they're not the cheapest to run.

[Millennium]

Thanks very much for the replies. I have a soft spot for Ryzen so may well go down that route

Best wishes

[Jonj1611]

Also have you considered the sound? They are ridiculously noisy. Just something else to consider.

[scaryjim]

... I have a soft spot for Ryzen so may well go down that route ...

Yeah, I was really surprised when I cracked out the calculations and realised how fast Ryzen is compared to Nehalem - we're used to thinking that Intel's IPC improvements stalled once Sandy Bridge was released, but Haswell was quite a big jump from Ivy Bridge, which means Nehalem to Haswell (and therefore Ryzen) is ~ 33% IPC increase. Given the power efficiency of Ryzen too (I suspect you could take an R7 1700 down to around 2.5GHz with a slight undervolt and have it pull ~ 45W) for anything requiring huge numbers of threads to run 24/7 it's a bit of a no-brainer (imnsho, of course ). Plus if you're underclocking rather than overclocking you should be fine with a cheap A320 motherboard...

[Millennium]

I'm more interested in performance (at least for the first month or two) then perf/watt. Not saying I'd OC to 4ghz+, maybe 3.8-3.9 on stock wraith cooler.

Did your maths on the Ryzen 1700 take into account any overclock? For performance, not power saving - there's no way I'm running a £500 per year server lol

[scaryjim]

... Did your maths on the Ryzen 1700 take into account any overclock? ...

Ooops, missed this (didn't subscribe to the thread!).

No, my calcs on Ryzen were based purely on stock clock speeds - it's only half as many threads, but with ~33% higher IPC and ~40% higher clock speed you get ~ 87% more performance per thread.

Overclocked to ~3.8GHz a single Ryzen 7 should give 15% - 20% more performance than 8 quad core Nehalem Xeons @ 2.13GHz. But of course you could always go Threadripper and get double the performance from a single socket...