Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Should I buy ECC memory? (2015)

danluu.com

Post reply on HN
Print view View original

161–170 of 237 posts

Re: Should I buy ECC memory? (2015)

#161

Post by paulmd »

binarycrusader wrote: post #157
paulmd wrote: post #156

Earlier quoted context omitted.

Ryzen ECC support is a mess, no AM4 motherboard currently on the market has implemented ECC support fully and properly (not even Asrock). It's better than nothing but you would be a fool to rely on it. http://www.hardwarecanucks.com/forum/hardware-canucks-review... "Kinda sorta works but the manufacturer won't stand behind it" is bunch of bullshit. If your data is worth using ECC in the first place - it's worth using…

Ryzen ECC support is a mess, no AM4 motherboard currently on the market has implemented ECC support fully and properly (not even Asrock). It's better than nothing but you would be a fool to rely on it. Ryzen motherboard support is what is agreeably a "mess", not the processor itself, but at least it's functional on ASRock and select Gigabyte boards. As for "a fool to rely on it", not sure what you mean by that. The e…

> Also, no offense, but I'm not going to rely on hardwarecanucks as an authority on this subject.

Fine then. AMD says it's unvalidated and unsupported, is that good enough for you?

> I'm well aware that this isn't the full grade of ECC support offered by higher-end Xeons and chipset combos, but it's better than nothing and it's affordable.

So would you be OK with running Xeon engineering samples then? After all - they certainly pass the same "best effort" test. Personally since these are server ES hardware - I'd tend to trust it more than consumer hardware like Ryzen, especially given their comparative age/maturity.

I just picked up a 10-core Haswell Xeon engineering sample for $140 last week. 40% more multi-threaded performance than a Ryzen 1700. The X99 mobo I picked up from Microcenter for $60 doesn't have ECC support but a bunch of them do.

Or if you want something that's official and you know works, there are surplus Sandy Bridge Xeons very cheap nowadays. A decent bit more multithreaded performance than a Ryzen 1700 - but you'll be giving up single-threaded performance. http://natex.us/intel-s2600cp2j-motherboard-dual-e5-2670-sr0...

Or really - a full retail E5-2630 v3 is under $500 now on eBay. That's not really that bad if you just have to have everything in one box.

> So for me, I'm looking at the possibility of getting a single system that can give me decent gaming performance, good development performance, ECC support, and more, all at a price that leaves me with money for other components.

What it comes down to: if you want everything in one box then be prepared to shell out. Everyone has this market segmented out, including AMD (after all they won't stand behind Ryzen's ECC either). If you feel you need ECC, that's really not a valid solution.

If a Xeon doesn't cut it for you - sounds like you might be in the market for two boxes here. A server/workstation with ECC and good multi-thread performance, and a gaming machine that you can overclock and get the best single-thread performance out of.

(Also - in general, overclocking also seems kind of counterproductive to the aims to running ECC RAM - although I guess I haven't looked into that.)

Re: Should I buy ECC memory? (2015)

#163

Post by codinghorror »

spullara wrote: post #57

I reproduced this by bit-squatting cloudfront.net after reading about it. So many memory errors! http://dinaburg.org/bitsquatting.html Loved the variety as well. Sometimes though requests came to me the Host header was correct!

Wait so when someone typoes cnn.com as con.com, that is ipso facto a memory error? I guess I could see that if the characters are radically far apart on the keyboard? But doesn't a simpler explanation like "one person out of billions with Internet access typed the wrong thing" seem a lot more likely?

Re: Should I buy ECC memory? (2015)

#164

Post by intrasight »

I am typing this (finally!) on my new desktop build. I did mull over the decision for a while but finally went with Xeon and ECC. So the memory cost more - perhaps even twice as much - so what? I use my computer pretty heavily for my work - with several VMs running at a time. If ECC saves me a headache once a year, it will have paid for itself. If it never provides ANY benefit I will still not regret the peace of mind.

Re: Should I buy ECC memory? (2015)

#165

Post by qb45 »

yuhong wrote: post #138
user5994461 wrote: post #86

Earlier quoted context omitted.

It's an inappropriate leap. Consumers should have ECC memory too. However the consumer market has long decided to settle for ECC nowhere and cheap everywhere. ECC hardware comes at premium option that can easily be +100%. You need support in the memory, the motherboard and the CPU. Given the price difference, personal computers will have to live with the memory errors. People will not pay double for their computers.…

Bristol Ridge does support ECC BTW, but one problem is that you can't use ECC with x16 chips (because ECC is 72-bit), so with 8GB of RAM and 8Gbit chips you have to choose between non-ECC/ECC single channel with x8 chips and non-ECC dual channel with x16 chips. 4Gbit don't have this problem but will become obsolete especially when 18nm ramps up, and while DRAM prices should decline when that happens...

What's the matter with x8/x16 chips and dual channel? I don't think it should matter.

Or do you mean that if you want exactly 8GB then it's hard to find a pair of 4GB DDR4 ECC modules? Well, just get 2x8GB if you are a performance nut.

Re: Should I buy ECC memory? (2015)

#166

Post by qb45 »

sitkack wrote: post #109
sytelus wrote: post #55

Earlier quoted context omitted.

Google had done extensive studies[1]. There is roughly 3% chance of error in RAM per DIMM per year. That doesn't justify buying ECC if you have just one personal computer to worry about. However if you are in data center with 100K machines each with 8 DIMM, you are looking at about 6K machines experiencing RAM errors each day . Now if data is being replicated then these errors can propogate corrupted data in unpredic…

I have hit soft errors in every desktop machine that used ECC. Either I have bad luck, ECC causes the errors or third thing. I think ECC should be mandated for anything except toys and video players.

> I have hit soft errors in every desktop machine that used ECC.

Not sure if I should start getting nervous or just your RAM sucks ;) I get ECC errors only if I overclock too much, and I run the RAM overclocked all time. It's actually one of the reasons I wanted ECC.

Re: Should I buy ECC memory? (2015)

#167

Post by yuhong »

qb45 wrote: post #165
yuhong wrote: post #138

Earlier quoted context omitted.

Bristol Ridge does support ECC BTW, but one problem is that you can't use ECC with x16 chips (because ECC is 72-bit), so with 8GB of RAM and 8Gbit chips you have to choose between non-ECC/ECC single channel with x8 chips and non-ECC dual channel with x16 chips. 4Gbit don't have this problem but will become obsolete especially when 18nm ramps up, and while DRAM prices should decline when that happens...

What's the matter with x8/x16 chips and dual channel? I don't think it should matter. Or do you mean that if you want exactly 8GB then it's hard to find a pair of 4GB DDR4 ECC modules? Well, just get 2x8GB if you are a performance nut.

Yes, what I am saying is that it is impossible with 8Gbit chips, but possible with 4Gbit.

Re: Should I buy ECC memory? (2015)

#168

Post by MichaelMoser123 »

paulsutter wrote: post #69
lomnakkus wrote: post #29

Earlier quoted context omitted.

> If you look through the source code & postmortems from that era of Google, there are all sorts of nasty hacks and system design constraints that arose from the fact that you couldn't trust the bits that your RAM gave back to you. Details of this would be very interesting, but obviously I understand if you cannot provide such details due to NDAs, etc. I mean, I can imagine a few mitigations (pervasive checksumming,…

You need ECC /and/ pervasive checksumming. There are too many stages of processing where errors can occur. For example, disk controllers or networks. The TCP checksum is a bit of a joke at 16 bits (it will fail to detect 1 in 65000 errors), and even the Ethernet CRC can fail - you need end to end checksums. http://www.evanjones.ca/tcp-and-ethernet-checksums-fail.html

Crc checksums can be wrong if you have multiple bit errors like runs of zeros. (This resets the polynomial computation) http://noahdavids.org/self_published/CRC_and_checksum.html

but crc is good to check against single bit errors.

Re: Should I buy ECC memory? (2015)

#169

Post by [deleted] »

paulsutter wrote: post #69
lomnakkus wrote: post #29

Earlier quoted context omitted.

> If you look through the source code & postmortems from that era of Google, there are all sorts of nasty hacks and system design constraints that arose from the fact that you couldn't trust the bits that your RAM gave back to you. Details of this would be very interesting, but obviously I understand if you cannot provide such details due to NDAs, etc. I mean, I can imagine a few mitigations (pervasive checksumming,…

You need ECC /and/ pervasive checksumming. There are too many stages of processing where errors can occur. For example, disk controllers or networks. The TCP checksum is a bit of a joke at 16 bits (it will fail to detect 1 in 65000 errors), and even the Ethernet CRC can fail - you need end to end checksums. http://www.evanjones.ca/tcp-and-ethernet-checksums-fail.html

[deleted]

Re: Should I buy ECC memory? (2015)

#170

Post by tscs37 »

thraway2016 wrote: post #75
throwa38282 wrote: post #62

Earlier quoted context omitted.

NSA is not the primary threat here. More conventional legal mechanisms are. Home serving is just as vulnerable to the NSA.

Conventional legal mechanisms against your home server cabinet can be handled via full disk encryption and a reed switch on your cabinet door connected to your power strip.

Sounds fun until you have to open your cabinet door for legit reasons like swapping a faulty hard drive in your RAID array.
Post reply on HN