That math from that 1998 article is a joke. There's also some problem with how you extrapolated it out.
As you double the amount of RAM the error rates don't double. This shocked scientists because it doesn't make sense. Also, as die shrinks take place(there's been quite a few since 1998) and it was expected that as each die shrink occurs error rates should be slightly more than double, but instead it increased very little. Again, this wasn't expected by silicon scientists.
You should read up on the Intel paper on ECC RAM. I'd trust that a little more.
Personally, RAM failure in my experience is very rare. I have only seen 6 bad sticks of RAM in more than 20 years in computers. Strangely, they are heavily skewed to recent hardware. First bad stick was 2005-ish, seconds was 2008, the other 4 have been this year. I have no explanation for it. The 4 that were bad were from different machines, different brands, some on-line, some unplugged and in a corner for more than 2 years. I can't explain it, but I am a little skeptical of RAM right now considering how many bad sticks I've seen this year. The problem with bad RAM is there isn't necessarily any warning signs. No SMART, no failure to boot, nothing. If you don't shutdown FreeNAS and run a RAM test you may never find out you have an error until its too late. Since ZFS is geared to finding silent corruption, it is imperative that you be able to identify all sources. For bad RAM, that is only possible with ECC RAM. ECC RAM can repair single bit errors, but identify multi-bit errors. For most systems with ECC, multi-bit errors result in a system shutdown and a text message on your screen from your BIOS listing the error location(s). Sun/Oracle don't "require" ECC RAM for reliability. If you want to roll the dice, you are welcome too. Unfortunately it seems that all 3 failure we've seen on the forums involving RAM involved complete corruption of the zpool and its data. So Sun/Oracle's "requirement" for ECC shouldn't be taken lightly, but using non-ECC is a gamble. Frankly, if I were building a system, even one for home use, I'd always use ECC now. But my first FreeNAS system uses non-ECC and next time I have to do work on it then it will be upgraded to use ECC RAM. I see no point in spending big bucks to protect my data, then deliberately leaving out something like ECC RAM because of the relatively small cost increase.
As you double the amount of RAM the error rates don't double. This shocked scientists because it doesn't make sense. Also, as die shrinks take place(there's been quite a few since 1998) and it was expected that as each die shrink occurs error rates should be slightly more than double, but instead it increased very little. Again, this wasn't expected by silicon scientists.
You should read up on the Intel paper on ECC RAM. I'd trust that a little more.
Personally, RAM failure in my experience is very rare. I have only seen 6 bad sticks of RAM in more than 20 years in computers. Strangely, they are heavily skewed to recent hardware. First bad stick was 2005-ish, seconds was 2008, the other 4 have been this year. I have no explanation for it. The 4 that were bad were from different machines, different brands, some on-line, some unplugged and in a corner for more than 2 years. I can't explain it, but I am a little skeptical of RAM right now considering how many bad sticks I've seen this year. The problem with bad RAM is there isn't necessarily any warning signs. No SMART, no failure to boot, nothing. If you don't shutdown FreeNAS and run a RAM test you may never find out you have an error until its too late. Since ZFS is geared to finding silent corruption, it is imperative that you be able to identify all sources. For bad RAM, that is only possible with ECC RAM. ECC RAM can repair single bit errors, but identify multi-bit errors. For most systems with ECC, multi-bit errors result in a system shutdown and a text message on your screen from your BIOS listing the error location(s). Sun/Oracle don't "require" ECC RAM for reliability. If you want to roll the dice, you are welcome too. Unfortunately it seems that all 3 failure we've seen on the forums involving RAM involved complete corruption of the zpool and its data. So Sun/Oracle's "requirement" for ECC shouldn't be taken lightly, but using non-ECC is a gamble. Frankly, if I were building a system, even one for home use, I'd always use ECC now. But my first FreeNAS system uses non-ECC and next time I have to do work on it then it will be upgraded to use ECC RAM. I see no point in spending big bucks to protect my data, then deliberately leaving out something like ECC RAM because of the relatively small cost increase.