Prime95 - e8500: Core 1 ok, Core 2 encountering errors

After running it on blend for 2 5-hour tests, both times my CPU 1 ran the full duration with 0 errors but the second CPU would encounter an error within 30 mins to an hour. I currently have my FSB set to 1720 in the bios (~4.083 GHz) and the ram unlinked at 800 (it's 800 MHz DDR2). The Vcore voltage is set to 1.41v and everything else (VTT, Memory voltage, etc.) is set to auto. I originally had the voltage set to 1.36, but both processors would encounter errors very quickly so I upped it. Real Temp puts my average distance to TJ Max during full load at ~25 with my processor's core normally running at 72-75 celsius full load, 45-47 idle. Anyone have any input or suggestions as to why one of the cores would be grinding through Prime95 fine for 5-6 hours but the other encountering an error within the first hour?

By the way, the error encountered is: FATAL ERROR: Rounding was 0.5, expected less than 0.4. Hardware failure detected, consult stress.txt file.

Edit: Lucius's response was to a question I asked earlier, but the main post has been updated to reflect my current issue.

Edit 2: I use Windows 7 64-bit, by the way (in case the software isn't compatible or something).

Bump

I found one core would crash before the other, I also found my cores had slightly different temps. If it does this on Small FFT settings, then you need more Vcore or a slightly lower bus speed.

Treat them as seperate CPUs, and you can only go as fast as the slowest one.

I'm running mine at 4.37Ghz, but at 4.5Ghz I get Core 1 erroring.
I was able to do 4Ghz with a bump in Vcore but everything else auto like you.

You're running kinda hot though, at 4.37 @ 1.52V I don't get over 65/63C and normally at 100% load the cores are 62/60C). I'm using a Coolermaster Hyper NS520 (not the best but works well).

System specs? What kind of HSF?

Your temps indicate that you could use some better cooling.