ECC or Non ECC ?

[AltoR]

Hello you all

I plan to build a new machine and I have a very simple question: must I buy ECC or Non ECC RAM ? Does it change anything when rendering with VRay ? Do I risk to have some weird things happening ? When I was rendering with Mental Ray a few years ago, I remember I sometimes had strange spots on my renderings and I used Non ECC RAM so .... What do you all think of that ?

Thank you for your answers

[kein_plan]

i think, you have no choice in that question. it depends on your motherboard, what ram is supported. usually only serverboards work with ecc ram.

[Morne]

yes you pretty much answered your own question. Non-ECC is way cheaper also. (but as far as rendering go, I don't think you will notice any difference)

[Dariusz Makowski (Dadal)]

ECC is 1 time slower than non ECC

Also if you have ECC there is a lot smaller probability of crash/error on save and so on. Not impossible but a lot smaller.

[AltoR]

My board will support both ECC and non ECC RAM (Tyan S7010AGM2NRF server motherboard).
If I understand what you guys told me, ECC RAM is faster than non ECC: do you mean that rendering will be faster with ECC RAM ? If so, how many times faster ?
In fact, the key point is: I plan to buy NON ECC RAM because it is cheaper, BUT: if I risk errors when working with 3dsmax / VRay, then I will buy ECC RAM, definitely. The matter is that, so far, I am not sure of that risk and I even don't know if such a risk exists or not ...

Does anyone in Chaosgroup team know more about this ?

[Morne]

When DADAL said it is 1 time slower, he should have said that it is like the difference in driving 120km per hour and driving 119.5km an hour. You won't notice the difference. Also in general, here anyways in retail shops, clock speeds for Non-ECC RAM is much higher than for ECC RAM. That is because workstations usually demands more speed than servers, whereas servers demand more load and accuracy. Again, I don't think you will notice any difference in speed (with same clock speed RAM), or quality/crashes between ECC and Non-ECC.

But yes, would be interesting to hear from Vlado on this one.

[ior=0]

EEC is an error checking routine that RAM chips are designed to use (a bit like RAID for RAM, not really but a bit), where data integrity is paramount (servers, data-based etc.) I'm sure Wiki will go into more depth if required...
You often will have a choice in the motherboard BIOS to turn on the EEC functions, or not for the RAM (Parity, error-checking, scrubbing and the like), but honestly it will not be necessary for you rendering and as DVP3D said, if you did it'll be slower by about one clock cycle (or whatever).
Here is a very interesting article on whether fast RAM is actually any faster http://www.tomshardware.co.uk/core-i...iew-31748.html
So get the cheaper RAM and look for low CAS numbers. 7's are very good

[AltoR]

Thank you. Well, I'm going to buy the cheapest memory I will find, no matter what timings are because I believe timings only have a small influence on render times.