Is ECC RAM worth it?

[ninjazed]

Stupid question maybe. I'm getting ready to build another machine for high end multimedia apps (games, graphics, etc.) and I was wondering, with prices at an all time low should I go for the ECC (if the m/b supports it of course) or are there some performance issues involved? While I'm asking, is this DDR2700 stuff really that much better than a stick of Crucial or Infineon? Thanks all.

 

[Woody419]

ECC, error correcting ram is actually slower than regular, it has to double check data for errors. This is improtant for servers, not for home pc's.

 

[LordSwedish]

The guy above you is correct, but I'll enlighten some more.

ECC RAM isn't very effective at error correction anyway. It can only possibly fix 2bits out of a 32bit string of data at this point.
So for that, it's not worth it....

ECC RAM is slower, because like the guy above you said, it has to check the data as it is being processed.

ECC RAM is not very overclockable, if overclockable at all. If you want to overclock your RAM (it's a very cool/good thing to do), you should buy regular unbuffered, non-ECC memory.

ECC RAM is also a bit more expensive, especially with the rising prices of memory.

In fact the only thing I can see ECC ram for is if its ECC/Registered where you need it for motherboards with a fourth slot for memory.

Hope that brings you up to date.

 

[pm]

<< ECC RAM isn't very effective at error correction anyway. It can only possibly fix 2bits out of a 32bit string of data at this point. So for that, it's not worth it.... >>

It can actually only fix 1 bit out of 64-bit. But this isn't a problem because memory errors are typically very rare, and the 64-bits of a typical memory line are scattered all over the place so it is fairly unlikely that you will have a multiple memory errors. Besides, I don't see your point. Surely the ability to correct 1 error, and detect 2 errors is better than not having capability to do this at all.


<< ECC RAM is slower, because like the guy above you said, it has to check the data as it is being processed. >>

It is only slower in the case of a read-after-modified-write where a memory location is read immediately after it has been written. In the case of a typical read, ECC is checked while the data is actually being used, and in the case of a typical write, ECC is written after the data has been written to memory. Since a read-after-modified-write is fairly rare, the performance penalty is pretty low. It is typically 2-3% slower than typical memory and in some cases, the performance is identical. 2-3% is within the margin of error on several benchmarks.


<< ECC RAM is not very overclockable, if overclockable at all. If you want to overclock your RAM (it's a very cool/good thing to do), you should buy regular unbuffered, non-ECC memory. >>

Why would this be the case? The memory chips are the same, all that is added in is the ECC checking lofic which is checking for errors. Since this isn't typically a speed path, there is no reason why this logic should create issues when overclocking. In fact, if you are overclocking ECC's ability to check for memory errors may prevent system instability.


<< ECC RAM is also a tad more bit expensive, ecpsecially with the rising prices of memory. >>

It is approximately 10% more at most reputable memory dealers. For 256MB PC2100 this adds up to about $3-4 more even with the recent memory increases.


<< In fact the only thing I can see ECC ram for is if its ECC/Registered where you need it for motherboards with a fourth slot for memory >>

ECC is useful for data integrity. If your data is important to you, or your system uptime is essential then ECC is very important. Servers, workstations, and home computers that contain important data should all use ECC. If it saves you from disaster just once during the life of the computer, then it has more than paid for itself.

 

[ucla88]

pm is right on target with a well written response.
parity (and it's successor, ecc) used to be the rule in pc's. most other subsystems in your pc have error checking, and in what was basically a cost cutting move, the extra bit was dumped by the manufacturers. and this was given the spin "1-2% performance increase."

next time you get a bsod, pat yourself on the back because your system is 2% faster.

while not essential, ecc gives a bit of redundancy that is often well worth it.

 

[RaiderJ]

For those of you living at higher elevations (Denver!), memory errors can also be caused by solar radiation. I imagine that the percentage of errors caused by this is quite small, but it is something to take note of.

IMHO, a 2-3% speed gain isn't worth the risk of memory errors, especially if some BSOD show up. Nothing makes a game go by slower than restarts.

 

[NOE]

Actually, when there is big a solar storm going on, it could take out satelites and powerstations quite easily! But I doubt that ECC memory will help in that situation!

 

[ninjazed]

Wow. Great responses guys. Thanks much for the help, but....
I still wonder whether the extra chip would affect overclocked situations. I also wonder if the new stuff touted as PC2700 is really worth the extra ching. It would sure be nice to see some real world comparisons of the various types of RAM available today. 1-2% difference here and there is pretty lame.
Thanks again.

 

[Kingofcomputer]

when Crucial sells PC2700 at the same price as PC2100, go for it,
otherwise don't consider those OCZ so-called PC2700 at higher price.

 

[pm]

<< I still wonder whether the extra chip would affect overclocked situations. >>

I don't overclock - and I would think that most people who are worried enough about their data to buy ECC probably wouldn't either - so I can't help with direct experience. Intuitively, I can't see how ECC would hurt, since as I said to the best of my knowledge the ECC calculation is not the critical path for reading or writing. But whether it would help... it's hard to know although it makes sense that having memory that checks and corrects memory errors would be more helpful when you have a chance at generating memory errors than one that doesn't.


<< I also wonder if the new stuff touted as PC2700 is really worth the extra ching. >>

I'm not sure that I'd completely trust any motherboard claiming to run at PC2700 to work reliably with all DIMMs until there is more availability. Personally I'm more into stability than speed, so I'd skip it. But that's me.


<< It would sure be nice to see some real world comparisons of the various types of RAM available today. 1-2% difference here and there is pretty lame. >>

I'm not sure that I follow. You want comparisons of PC1600, PC2100, and PC2700? Or ECC?

 

[dc]

if the mobo doesn't support ecc, the ecc ram will just run like normal nonecc stuff without the performance hit, correct?