A few weeks ago AMD added a few new special SKUs to its Llano lineup, one of which really interested us as it came with an unlocked multiplier. The A8-3870K we have here with us today has been put through one of our famous bench sessions, follow us as we go through what we did to accomplish our highest speeds. Did we really hit 6GHz? Sort of. 

Below is the A3870K we used after it had gone through a 5 hour LN2 session. You can see that it is still so cold it refuses to defrost even after being under our 1000W heat gun for a minute or two. The beauty of such cold is that AMD CPUs for the most parts are an LN2 Overclocker's wet dream, they lack any cold bugs and are pretty forgiving even after some harsh voltage treatment. Today we will provide sort of a recipe for how we accomplished our overclocks, so that you at home and try it yourselves!

Ingredients:

  1. AMD Fusion A8-3870K
  2. Decent A75 board with a BIOS to support the multipliers of the A8-3870K (We used ASUS F1A75-V Pro)
  3. LN2 POT or container to act like a large heatsink that you pour LN2 into
  4. Digital Thermometer that can measure to -200C, along with K-Type thermocouples
  5. Silicon based conformal coat (we used a spray on)
  6. Art eraser, you can buy this from an art store. 
  7. Neoprene for the POT and the board
  8. Armaflex Insulation
  9. Thermal Paste that can withstand very cold temps (EVGA Frostbite is what we used, but there are many more)
  10. Discrete GPU
  11. A single low-density memory stick
  12. A 700W+ PSU, preferably with a strong single 12v rail
  13. Fans to blow vapour away from the board, and keep air flowing
  14. A lot of paper towel and tape for soaking up the wet
  15. Cannisters of LN2
  16. Faith in your CPU and Motherboard, and most importantly yourself.

However we first need to go over some of the limitations of the CPU, and compare against the A3850 which we used in our Llano Round-Up. 

Most notably you can see that the max multiplier on the A3870K is only 47X, which means the FSB has to be increased to around 135MHz to hit 6GHz. 

 

A8-3870K

A8-3850

CPU Cores

4

4

Clock Speed

2900MHz

3000MHz

Integrated Graphics

HD 6550D / 600MHz

HD 6550D / 600MHz

Memory Support

Upto 1866MHz

Upto 1866MHz

Max Multiplier

47X

29X

TDP(Watts)

100W

100W

Chipset (Socket)

A75/A55 (FM1)

A75/A55 (FM1)