Need help OCing A8-3780k!

Hey everyone, I recently built a new computer and I've been playing around with different overclocks for the past few days, but i've been running into problems with CPU throttling.

Here are my components:

APEVIA Case w/ 500W power supply

AMD A8-3780k APU w/unlocked multiplier

Enermax ETS-T40 CPU Cooler w/ 12cm Fan

ASRock A75M-HVS Micro ATX Mobo

60GB OCZ Agility SSD (OS)

2TB Seagate Barracuda (Media)

2 x 4GB Corsair Vengeance Low-Profile 2133Mhz RAM

Gigabyte Radeon 6670HD Discrete GPU (for Crossfire with APU)

I also have 2 x 12cm intake fans on my case (one front one side) and 2 8cm exhaust fans on the back.

I used the included thermal paste to attach the CPU cooler with no problems, and I've managed stable overclocks up to 3.5Ghz using OCCT and Prime95... (104FSBx34) CPU voltage 1.4625V and CPU NB at 1.250V

I want to use AHCI mode for my SSD as supposedly it's faster, so I can't raise the FSB above 104 without losing my HDMI/VGA outputs.

I've also been playing around without any FSB increases and actually managed to get a stable 3.4Ghz by undervolting slightly.

Seeing as the HD6670 will be taking the brunt of the graphics load, and from what I've read an overclocked integrated GPU is negligible in crossfire performance with Llano, I won't be overclocking the IGP, just running it in crossfire at stock settings for an FPS boost.


My goal for this OC is 3.5 - 3.6Ghz CPU, but when I run OCCT or Prime95, the CPU throttles down to an 8x mulitplier when core temp. hits 47 Celcius. I realize that the actual core temperature in AMD chips is offset, but using HWMonitor I get similar readings.

I'm concerned my OC will throttle on me during regular use, is this a concern?

if anyone else is running an OC Llano build, any suggestions for FSB/multiplier settings as well as voltages?

Ideally I'd like to run voltages as LOW as possible while acheiving as close to 3.5Ghz as I can.

I looked up vrm cooling, it looks intriguing but I'd like to work with the components I have now. I still can't get the throttling down in synthetic benchmarks.

My current overclock is CPU 1.4375v and CPU nb 1.0675v fsb 102 34x multiplier for 3.5ghz. Running stable so far.

Will I have to worry about throttling when playing games?

Thanks for the detailed reply, I didn't realize the vrm required cooling as well... Is it possible to use the fan or heat sink from the a8-3780k stock cooler for cooling the vrm?

This is my first attempt at overclocking, so I guess I didn't research as much as I needed to. Are there any reasonably priced vrm cooling solutions I could implement? Is it possible to purchase heats sinks for the vrm?

I just did some quick research on VRMs and MOSFET cooling... I'm really disappointed I overlooked this; if I had known about VRM cooling and how important it is to an OC I would have been more picky with my motherboard selection. However, this is good experience, I'm sure my next build will be much better.

If I order some copper heatsinks similar to the ones in the post above, is as easy as sticking them on the vrm mosfets near the CPU socket?

I have an 80mm fan from my stock heatsink, think that might be useful? It connects to the CPU fan1 connection though... will that be a problem? My Enermax cooler came with a daisy chain adapter so I can put it in the chain with my case fans if needed.

I ordered the MOSFET heatsinks last night from Sidewinder Computers 15 Dollars shipped to Canada... Not bad!