if you wanna get to 1866Mhz try loosening the timings to 8-8-8-24 or 9-9-9-24 and set it to run at 1866... you might also need to add voltage a little bit if its unstable.
PS: I'm not sure this will work with your system though. You have a phenom II X4 cpu. Those cpus support only up to 1333Mhz by amds spec. People still have success running the ram at 1600 but it doesn't always work and is not guaranteed by any means. I had 8GB of 1600 G.Skill Eco Ram (7-8-7-24) with a Phenom II X4 and it wouldn't run 1600 stable. It ran 4GB at 1600 stable but when running all 8gb I had to downclock to 1333.
Thanks for the reply, I appreciate it. I've got it at 1600 7-8-7-24-37-2T, but when I tried tinkering with it and lowering the timings any further and upping the voltage, it either wouldn't boot and I had to hit the MemOK button on my Motherboard or it failed somewhere in the 4th or 5th test of MemTest. =/
I'll try your suggestion and see which ends up faster/more stable. If it doesn't work out I might end up just having to run them at stock, which wouldn't be so terrible seeing as it's been over a year and I just now found some obscure settings in my BIOS that were putting caps on my voltages and overriding my overclocking, so I was running at 1333 9-9-9-28-40-2T. I thought I just sucked at overclocking, but apparently I was being dumb, lol.