AMD Llano overclocking tips?

[BeepBeep2]

Using a UD4H, so far it has been a PITA
My GSkill Pi, SPD is detected but only 2GB usable, so I went to RipjawsX and those work alright.

Highest ram divider (1866) works somewhat, seems like I can't OC with it.

There seem to be major FSB holes, 100-110 seemed ok and 138 worked too, but 133-135 didn't.

I am in a time pinch (I have 4 systems to bench in a few days), just looking for quick tips here otherwise I would screw with it more

Thanks,
Sam

[The Stilt]

Use the 1:8 (DDR-1600) ratio instead.
Gigabyte has an "interesting" way to configure the NCLK (NB) domain...

With the 3:28 (DDR-1866) ratio the NCLK is set to /5 divider (720MHz NCLK) instead of the AMD specified /4 divider (900MHz).
However with 1:8 ratio the NCLK divider is the same. This means with 1:8 ratio your NCLK will be closer to the MEMCLK.

E.G DRAM DDR-2400:

1:8 Ratio: BCLK = 150MHz, DRAM = 1200MHz, NCLK = 1080MHz.
3:28 Ratio: BCLK = 128.6MHz, DRAM = 1200MHz, NCLK = 926MHz.

This means 1:8 ratio is much faster, especially in 3D.

All of the higher-end Gigabyte FM1 boards should easily do 150MHz+ BCLK with current bioses.

Generally the even DRAM dividers work better on Llano as they use different DRAM Phy ratios and dividers than the odd (e.g 3:28) dividers.

With 1:8 MEMCLK ratio you will however reach the max NCLK frequency quite easily.
On air the NCLK usually maxes out at 1100-1200MHz with ~1.25V depending of the leakage levels.

The fastest way to test the IMC/NB stability on APUs is to run 3DMark06 GT-1 or 3DMark11 Combined test.
In case the IMC/NB is failing the GT-1 usually flips within 5 seconds or so

[BeepBeep2]

Thank you The Stilt

Is GPU frequency tied to BCLK?
It seems to be adjustable separate but some reviewer said the adjustment didn't do anything.

I am trying to achieve highest 3DMark06 on air cooling (H70) but I also want to try and find the highest memory clock. I'll have LN2 probably tomorrow or the day after.

A lot of times when I bump up BCLK the board restarts but does not POST beep or output any other beep codes. I don't have a diagnostic board so I can't tell what it is doing...I have been using the DVI-out, which I assume is better for BCLK OC than VGA(?)

[The Stilt]

On Llano everything is tied to BCLK (thru MainPll).

SCLK = BCLK * MainPll / SCLKDIV.

On 3850 & 3870 MainPll FID is 36x (3600MHz @ 100MHz BCLK) and default SCLKDIV is 6 (3600/6 = 600MHz).

MainPll FID cannot be altered on Gigabyte boards anyway, so you can calculate the SCLK: BCLK * 36 / SCLKDIV.

The other clocks usually start failing at 160MHz+ BCLK, the first ones to fall are DisplayCLK (VGA) and SATACLK (AHCI).
These two you will loose at around 120MHz BCLK.

[BeepBeep2]

Thanks for the info, I had no idea it worked that way

[BeepBeep2]

Well this afternoon I tried again and the board does not post and there are no beeps or video.
I tried CLR CMOS, remove unnecessary peripherals and even resorted to shorting HOLD# pin on main BIOS chip to GND to induce backup bios.

I don't understand.

[EniGmA1987]

Isnt Llano really finicky with what type of RAM is installed? Maybe it just really doesnt like your sticks.

[BeepBeep2]

Well now the system doesn't post at all so I don't know what to do. These sticks are PSC so there should be no issue, tested on BD up to 2500 7-11-7.

The CPU still gets warm and so does the PWM/VRM section.

No video out and no post beeps.

[EniGmA1987]

Sounds like a problem with the CPU to me.

[BeepBeep2]

I was thinking I would get beeps from the motherboard speaker then.

[The Stilt]

No diagnostic card available?

Measure the VDD(C), VDDNB, VDDP/R voltages to ensure they are ok.

I replaced the VDDP/R controller on my A75M-UD2H prior the "Farewell Llano" run.
The ISL6545 controller found between the socket and the first PCI-E x16 bus was burned, as well as the resistor used as a "fuse" for the VIN voltage of the controller.

[BeepBeep2]

Ok, once I figure out measuring points O.o


I am not always that bright.

[BeepBeep2]

Regardless of measuring any voltages, board is dead.
Something on it, anyway...

It is under warranty so gonna RMA. Disappointed, needed to bench for HWBOT Team Cup...which ends Tuesday