After the death of my 3570k box, note to everyone don't slip and stick a screwdriver into a running pc's mobo XC, im using a bulldozer 8350 in my old m5a99x evo, everything fine but a little slower then my ivybridge was but.... Im benchmarking my pc to see how good it is. In prime95 running smallfft the multiplier in CpuZ will every 10 seconds drop from x20 to x17 for a second then jump back. all cores are fully loaded. is this normal? Can a AMD ninja give me a hand?
It is throttling. Going from Intel where you can just ramp the oc as much as you like to a AMD set up can be a bit of a pain in the ass, it is not as simple with the FX chips. There should be a setting to disable APM (I think that's it) and to raise the cpu current on that board ( I have one here but not at a desk so cannot check for you). Also if you are stress testing after disabling the power control the VRM section will get hot as hell, you will need a fan over them ideally. Finally you will notice with the power management disabled that when stress testing they are VERY difficult to cool, once they get over say 65 degrees your stability is going to be at risk. Hope that helps, seems stupid at first but it is just the way they are made, under full load they are designed to not run at full speed and you have to tweak and cool them well to get them to run "flat out" so to speak.
Watch your temps as mrbungle says. If my 8320 gets to 68c it will drop to 1.7ghz until it's back down to around 63c before the clocks reapply. What cooler are you running? I'd really suggest using a H80 or H100 if you're aiming for a big overclock.
im not over clocking and im using a hyper212evo with a noctua120mm, the focused air flow model, hwmonitor shows max temp of 54c
Sounds like APM, or AMD Thermal Control, (I can't remember quite which one causes it) that forces the chip to clock down if it's nearing Thermal Threshold while under maximum load. Murder AMD Thermal Control if you can find it, if not; Disable APM. They're helpfully separate on my Crosshair V, but I'm not sure about the M5a99x. APM is actually semi-helpful if you've got Cool and Quiet, as without it; FX chips just seem to run at either absolute minimum clocks (1.6ghz in my case) or Flat out, so there's no middle steps, just an all or nothing switch, APM gives it the middle steps back, so it'll dynamically clock a little better.
I disagree. I used to see the same on my 8120 when I was watercooling, CPU would be at 20-30 degrees and still throttle purely because of 100% load across all threads. (Watercooled VRMs too.) Try and disable AMD Thermal Control, Shelley, It should solve the issue, if not alleviate it somewhat.
OK using amd overdrive to monitor core speeds and temps, well they make the hardware and the software so hopefully its useful XD I notice even though temps never go above 43c and 1.3375v, the weird down clocking only happens on alternate cores so im guessing its just a weird effect of the 2 cores / 1 module hardware sharing
