The temptation of a Ryzen-based machine for my next office workstation

May 5, 2017

My office workstation is the same hardware build as my current home machine, which means that it's also more than five years old by now. I was not necessarily expecting to replace it soon, but this week things have started to happen to it. First there was an unexpected system lockup and reboot and then today my CPU reporting thermal throttling, with the always fun kernel messages of:

CPU1: Core temperature above threshold, cpu clock throttled
CPU3: Package temperature above threshold, cpu clock throttled
CPU2: Package temperature above threshold, cpu clock throttled
CPU0: Package temperature above threshold, cpu clock throttled
CPU1: Package temperature above threshold, cpu clock throttled

(All of my system's fans are working; I checked. Some sources suggest that the first step here is to take the CPU and heatsink apart, clean off the current thermal paste, and re-paste it. I may try to do this on Monday if we have thermal paste around at work, but the timing is terrible as I'm about to go on vacation.)

For obvious reasons this has pushed me into thinking more actively about replacement hardware for my office machine, and when I start thinking about that, I have to admit that building an AMD Ryzen based machine feels like an attractive idea despite what I said about Ryzen for my likely next home machine. There are either three or two sensible reasons for this and one emotional one.

The first reason is that I generally do more multi-core things on my office machine than on my home machine; I run VMs (and might run more if it had less impact on things) and I compile software more often for various fuzzy reasons (and some of the time I care more about how fast this happens, for example if I'm bisecting some problem in an open-source project like Firefox). In theory this makes single core CPU performance less important and many well-performing cores more useful, especially in the future as more things become multi-core enabled (for example, the Go developers are working on concurrent compilation of single files).

The complicated and only potential reason is that work is more price sensitive about things like CPU costs than I am for my home machine. I started out thinking that the Intel i7-7700K was more expensive than the Ryzen 7 models, but this turns out to be wrong; at current Canadian prices, the i7-7700K and the Ryzen 1700X are about the same price (the Ryzen 1800X is clearly more and the Ryzen 1700 is only a bit cheaper). However these are still relatively expensive CPUs, so I might well get forced down to, say, something in the range of the i5-7600K and the Ryzen 5 1600X. At this level people seem to think that the Ryzen 5 is the relatively clear winner; you don't lose as much on single-core performance and you pick up a significant edge in multi-core work.

The third reason is the possibility of ECC support. At least some AMD Ryzen motherboards do seem to actually support this in practice and if I more or less get it for free, I'll definitely take it. It's only a 'nice to have' thing, though; I wouldn't give up anything substantive to get it, even (or especially) on my office machine.

The emotional reason is that I want the plucky underdog AMD to make good, and I want to support them. I don't particularly like Intel's domination and various things it leads to (such as their ECC non-support) and I would be perfectly happy to be part of giving them a real challenge for once. If a Ryzen based system is competitive with an Intel one, I'm somewhat irrationally biased in favour of the AMD option.

(For example, going with the AMD option would require a graphics card and I haven't looked at the relative level of motherboard features that I'd probably wind up with. My emotional 'I would like AMD' reaction has pushed those pragmatic issues out to the periphery. For that matter, apparently there are memory speed issues with AMD Ryzens and 32 GB of RAM, and memory bandwidth may matter to at least some of what I do.)

Comments on this page:

By James (trs80) at 2017-05-06 09:27:36:

If you have some mayonnaise around the office that apparently performs quite well as a thermal compound:

Is the 32GB RAM speed thing actually a significant performance drop?

By Some Anon at 2017-05-06 14:32:47:

You can use all sorts of impromptu things for thermal grease - a friend of mine used toothpaste once. That's really only suitable as a "I just need it to work for two days until I can get more real grease", though. The conventional wisdom in the PC enthusiast community seems to be that fancy overclocker grease (Arctic Silver is the oldest and biggest name) is only slightly better than generic white zinc-oxide packets in terms of temperatures, but much better at not drying out and causing problems like this a year or three down the line.

If you're using the stock CPU fan you might consider getting an aftermarket one. You can spend arbitrary amounts of money on the fanciest models, but basic tower coolers with quiet 120mm fans start at about $25 (US). Ryzen heatsink mounting is in a bit of flux right now, but since the type of people who buy fancy coolers and the type of people who buy brand-new CPUs overlap, you can find a lot of heatsinks that are compatible with both Intel and AM4 sockets, or that have a mounting kit available to make them compatible.

By cks at 2017-05-07 03:28:14:

The Ryzen memory speed stuff is obscure to me, although I know it exists. Basic research suggests that non-overclocked Ryzen supports DDR4 2133 at most with four DIMMs (if you have single-rank DIMMs), and DDR4 2666 if you have two single-rank DIMMs. Dual-rank DIMMs go slower, down to 1866 MHz for four of them. Intel's Kaby Lake CPUs support DDR4 2400, apparently more or less universally. For more fun, apparently the situation is changing frequently as AMD and motherboard vendors do stuff. How much performance difference this makes is unclear, but various sites say it can make a real difference (although I think they're usually overclocking). And I have no idea how you figure out who is selling single-rank DIMMs versus dual-rank DIMMs.

(This mess, like the ECC mess, is the kind of thing that tempts me to throw up my hands and punt back to Intel.)

Written on 05 May 2017.
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