Quasebarth: Out of curiosity, may I ask what is so important about ECC support? As far as I unterstand it, the error-correction is mainly important for much higher reliable system, such as servers, scientific workstations, navigation computers or maybe financial calculations. The trade-off for this reliability is higher costs and maybe even less speed.
I just do not really understand how I would benefit from ECC in an gaming rig or standard home computer.
No, no forget all this. Here is my practical experience, no theories and stuff:
ECC is simply ability to correct data corruption (and code=data) up to certain limit.
It can detect and correct 1,2,4 bits from 8 bits (byte). Without ECC the data will corrupt and travel further unnoticed.
Bit flips happen and will happen - different chances, different sources: from cosmic radiation... to faulty hardware or shielding. Sometimes it just can happen - for example on DDR4 the speeds become so fast, the error rate is too high, too probable, so they install CRC checks on write, to punch the probability withing "
acceptable". Yet those CRC checks do not correct errors, but re-send the data - cheap solution to ECC at cost of loosing some performance (again, weighting of whats acceptable for every customer layer).
ECC is already installed in CPU in caches. But its still an "option" for RAM. The cost of ECC - one extra chip on memory bank, instead of 8 -> 9. instead of 16->18. Its cents. Of course market may overproduce/underproduce, but raw cost is this. Very affordable, but market behaves differently.
The speed - ECC brings no speed penalty. None. There is "registered" ECC ram type, now that has latency penalty, but not due to ECC, but due to "register" - a buffer that allows substantially higher bank capacities. But this latency is again not due to ECC logic per se. Unbuffered ECC does not have this.
Now about probability and damage extend.
- The probability for desktop machine is at least once per year, from one byte - to few bytes.
- And about the damage - it depends where it happens... great factor.
If it happens in the data, you may have damaged JPG,.. some useless in browser cache.. or some very important, which you never backed up. Your operating system might crash. Or it may just display some weird error and continue on. Its truely random.
What ends up is this: do you accept playing russian roulette over your whole address range in your machine, over your whole data once a year for, perhaps, a bit slightly higher cost of your memory banks? If you need additional, global, effects, see "Bitsquatting".
The motherboard manufacturers think - compared to your data is worthless, few cents in your wallet are more important. If you are other opinion - go for ECC. if you are not - use usually cheaper non-ECC. I have a file and media server that runs with 8GB of ECC DDR2 and $20 AMD CPU, and it works just fine,.. but Intel thinks that you should pay +$300-1000 premium for ECC. At least until hardware gets pulled from companies and is purchaseable used for small fraction of this price. Its intel nature. Until now AMD offered ECC virtually at no additional cost. That was a BIG difference, now gone.
