Computer stable?

I have a new home built system:
-AMD Quad 9950 Black Edition, with a Noctua NH-U12P heatsink
-Gigabite GA-MA-790X-DS4
-2x 2Gb DDR1066
-Thermaltake 750W toughpower modular
-ATI X800XL (I ordered a HD4870, but it was defective..., waiting for a replacement)

Anyways, I wanted to test stability using OCCT stress test. The result is that it always fails after about 1-10 minutes, although there is no overclocking, and the temps are stable at 45 degrees (Should be stable...). I get error code 4: Calculation error.

Other stress test pass with high colors.
I have seen in other forums not to stress, as sometimes OCCT will bug, so it's a software, and not hardware problem.

What did bother me is that some time ago, my HD4870 fried after my PSU tripped, so I wanted to monitor my power supply, during the stress test. My Vcore and 5V is rock solid stable, the 3.3 is alright (bit of fluctuation), and the 12V fluctuates a lot.

So here are my three questions:
1 - Should I be worried about OCCT errors? Can I just shrug it off to software bug?
2 - Is my power supply stable enough for my components? Is what I am seeing alright?
3 - Even if what I am seeing is OK, should I expect this kind of behavior from a High-End PSU? It's supposed to be very good quality.

Thanks!
PS everything is up to date, bios & everything

Pictures attached

The fluctuation on the 12V is only 50-70mV so I would not think it is anything to worry about.

As for the OCCT stability vs is it a problem, we will need someone with more skills in that area to comment.

I ran prime95 in mixed mode, and after 30 minutes or so, one of the workers stopped due to a round-off error. This happened 3 times.

So I guess there is definitely something wrong. The test was in mixed mode (FPU+RAM), so I tried the small FFT test (FPU only), and the test ran overnight for 8 hours with no problems. Guess this probably means the culprit is the RAM...

I'm going to run a Memtest86+ tonight to see.

I'm not sure whether or not I hope my ram is defective

Faults are a strange thing, you don't really want them but if something strange is going on it is better to know what it is.

RAM is a great cuplrit at causing strange errors that can be hard to pin down sometimes, good luck with those tests.

Turns out it's the ram. I have some PC8500 sticks, but it turns out they can't handle such frequencies...
The good news is I won't have to RMA.

I'm going to try and play with the timings and voltage and see if I can get them to stabilize.

When you say your 12 volt rail fluctuates a lot...what exactly are the differances
+/- 2%
+/- 5%
more
And is this done with a Digital Multi-Meter ???

I really don't like ThermalTake PSU's anymore...they do fluctuate

The measurement is OOCT's graph. You can see them on the above-posted graph.

Yes but he wants to know what OCCT used to take the measurements. Some boards, as I assume yours does, record and report this, others (like my laptop) don't. You'll usually get a more accurate result using a multimeter as they are usually more accurate.

It was all OCCT reading on-board sensors. I didn't load speedfan pr everest or anything like that.

I don't have any multimeters on me.

In my opinion you should try to invest in a Digital Multi-Meter...Look around for sales...especially now that its Christmas....Last year I picked a $59.99 one for $19.99 on sale.
And Software readings are usually not that accurate...My Windows reports my 12 volt as 11.93 volts and Smart Guardian reports 11.77 volts...when I plug in my Dig Multi-Meter is a Solid 12.07 and never goes under 12.03 with 100% CPU load