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Is ECC RAM recommended for use in workstations, or is it something that only gets used in servers? If non-ECC RAM works in PCs, why would we need ECC RAM at all?

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7 Answers 7

up vote 16 down vote accepted

As stuff is stored into, left, and eventually pulled out of RAM, some corruption naturally occurs (theories vary, but the one with the most weight right now is EMI from the computer itself). ECC is a feature of RAM and motherboards that allows detection and correction of this corruption.

The corruption is usually pretty minor (ECC can usually detect and fix 1-2 bits per 64 bit "word" - and that's waaaaay beyond the typical error rates), but increases in frequency with the density of the RAM. Your average workstation/PC will never notice it. On a server where you're running high density RAM 24/7 in a high-demand environment serving critical services, you take every step you possibly can to prevent stuff from breaking.

Also note that ECC RAM must be supported by your motherboard, and the average workstation/PC does not support it.

ECC RAM is more expensive than non-ECC, is much more sensitive to clock speeds, and can incur a small (1-2%) performance hit. If it helps, an analogy that works is RAM to RAID controllers. On your PC, that hardware-assisted software RAID built into your chipset is great protection against single disk failures. On a server, that would never be enough. You need high-end, battery-backed fully hardware RAID with onboard RAM to ensure that you don't lose data due to a power outage, disk failure, or whatever.

So no, you don't really need ECC RAM in your workstation. The benefit simply will not justify the price.

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ECC RAM gets more interesting as memory sizes grow. The probability of a single bit error in a machine with 8GB of RAM is quite a lot higher than it was in the days of a 640K PC/XT, simply due to the larger number of bits. On a database server where that RAM might be in a disk buffer, a bit error can corrupt disk storage as well. Generally you would expect to use ECC memory on a server.

Some workstations (particularly those with Xeon or Opteron CPUs) take registered memory, which pretty much only comes in ECC flavours anyway. On a desktop PC you may view it as overkill.

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If this article is anything to go by, then you should use ECC RAM.

It's not just a matter of "I don't run a server, so I don't need it". It depends how much you value your data. It's not just a matter of occasional crashes - the problem is you could get corruption and have no way of knowing that it's going on.

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ECC RAM is designed to aid in preventing and fixing memory based errors, usually using some sort of hamming code or modular redundancy. This is very useful in servers that contained important data, or need high availability, but it comes at a cost.

Whilst its probably worth paying the extra for your important servers, do you really want to do so for your desktop machine, does it matter if there is the occasionally memory error? Sure it matters if your SQL database drops some data during a transaction, but do you care if your word document is affected by a slight memory blip?

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If you want a reliable workstation then you want ECC RAM for it. It will crash less often and work done on it and documents cached in RAM will not be randomly corrupted.

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3  
It seems like an immeasurably small chance of improved stability. The only RAM-related crashes I'm aware of on workstations are due to bad RAM or bad applications, never something that ECC would have prevented. It makes some (read: still only a tiny bit) of sense on servers where you're crunching terabytes of data constantly, but on workstations maybe the only thing that gets close is high-end graphics rendering or video processing. In short, I think you can get a completely reliable workstation without ECC RAM. –  Chris Thorpe Feb 8 '10 at 4:55

ECC memory now costs about the same as non-ECC memory, as prices have dropped. So check prices; if prices are anywhere close, buy ECC if your workstation accommodates it.

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An additional benefit of ECC over what was mentioned above is that you can detect bad RAM. While running a long memtest86 session will usually find any problems, there may be very specific problems with the RAM which only show up rarely and in certain use cases. This can still happen much more frequently than the corruption that perfectly good ECC RAM is designed to protect against -- maybe once every month. So if you install monitoring software, you can be sure that your RAM is good, or replace bad chips. Still a marginal benefit, but as ECC memory is not much more expensive than normal RAM, it may be worth it.

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