It hasn't exactly been determined how to stress test a quad-core processor.
Running four instances of Prime95 will work. Not sure about running two instances of Orthos though..
Here's what you do with Prime95:
I used these exact instructions with stress testing my dual-core, and it works. I just modified the steps a bit for four cores rather than two. Hope it works!
1) Install Prime95
2) Create four shortcuts of the installed Prime95
3) You need to change the shortcuts so they run as different instances. Right-click one of the shortcuts, go to "Properties", then to the "Shortcut" tab. At the end of the target line put a blank space, and add -A1 (so it’s “ –A1”)
4) Repeat step three for two other shortcuts you created (but change the extra characters you put at the end). You should now have one shortcut that is not modified, and three other ones modified differently (A1, A2, A3).
5) Open all four instances (the four shortcuts).
6) On the top toolbar, go to Advanced > Affinity, and uncheck "Let program run on any CPU". Leave the 0 in the box for the first one, and put a "1" in the box for the second instance.
7) Repeat step six for the other two instances. You should now have four instances of Prime95 open, each with a different affinity (0, 1, 2, 3).
8) Go to Options> Torture Test > Custom > Memory to use in (MB). This should be 1/4 of your AVAILABLE system memory for each instance.
As an example, I have 1GB of RAM, a dual-core CPU, and Windows XP that uses 256MB of RAM while idle. This means that I have 768MB of
available RAM. Now, I divide 768MB up in half for my two cores, so I set each instance to use 384MB of RAM.
As for your situation, just take about 256MB of RAM from your total memory, then divide that into four. Input that amount into each of your instances of Prime95.
9) Click OK and let it run!
Stress tests should be left for a burn-in period to test stability, preferably 12-24 hours. You should also run memtest afterward to test the RAM (I assume it's also overclocked). Then, you can run a few benchmarks to see how much of a performance gain you have.
Just ask for clarification if something is not detailed enough.
I sincerely hope this helps!
