Feeding a 1070 Ti with a tiny processor

[Paragon]

Did you try to force CPU clock?

Code: Select all

sudo cpufreq-set -g userspace
sudo cpufreq-set -f 2000Mhz

Yeah. It accepts the command but the frequency doesn't change. I just got Ubuntu working on another machine (the A10 APU on an ASRock FM2+ board) and all the frequency scaling works fine. So for the Athlon 5350 APU / Gigabyte AM1 board, something must be breaking in the background. I'm going to try an older version of Ubuntu, perhaps 14.04, which was the version around when Socket AM1 was released. We will see if that fixes things.

[Theodore]

Sometimes Linux only shows you the base speed, not the boost speed.
If you're running a mobile device, with low base clock speed (especially if ran in powersaving mode), it might not show the CPU ramping up to boost speeds.

On a low power Celeron processor, I've had Ubuntu tell me my CPU was running at 1,6Ghz, despite the CPU supporting 2,48Ghz boost speeds.
It turns out that the CPU did run at 2,48Ghz, it just wasn't shown in terminal commands.

800Mhz looks like a power saving setting on a mobile device.

[Nathan_P]

Are you using the cpu's because you have them on hand or because the budget wont stretch to something better? I have a 25w tdp chip driving a 1070 and 2060 and i'm currently getting 1.3m PPD, idle power draw from the wall is 68w and full load is 400w from the wall.

Admittedly the cpu is an E3-1230L v3 which is not a cheap option but it was built to cut system power usage to a minimum.

[Theodore]

Are you using the cpu's because you have them on hand or because the budget wont stretch to something better? I have a 25w tdp chip driving a 1070 and 2060 and i'm currently getting 1.3m PPD, idle power draw from the wall is 68w and full load is 400w from the wall.

Admittedly the cpu is an E3-1230L v3 which is not a cheap option but it was built to cut system power usage to a minimum.

Interesting!
My portable folding Machine consists of a 2070 + 2060 as well, fed by a 56W Celeron G4900 dual core processor on a mini it's board. I'm averaging at 1.7 to 1.8M PPD, occasionally topping 2.1M PPD.
The 2070 is running from a PCIE 16x slot at 8x speed, while the 2060 runs from the mPCIE (m.2) slot via a riser at 1x speed.
System power 65W, but I run the 2060 at 130W, and the 170 at 140W, resulting in 325W at the wall. Occasionally I hit 350W.

[Paragon]

So I confirmed I'm seeing real clock rates...it's not just 800 MHz as a nominal number. Refreshing with the cpufreq-info command shows some slight variation (799 MHz, 801 MHz, 800 MHz, etc). I've got plenty of other computers on hand...the point of this microATX build is to just look at what can be done from an efficiency standpoint (writing another blog article for greenfoldingathome).

The latest news is that I did an identical Linux install on a different AMD APU machine (AMD A10-7700K quad core APU on an ASRock Socket FS2+ board instead of this AMD Athlon 5350 quad core APU / Gigabyte AM1 board). This time everything seems to work as intended. The 1070 Ti is doing somewhere around 650K-750K PPD at the moment with 90-100% GPU usage (no overclocking yet). The A10's clock rate moves around from the low 2 GHz to 3.6+ GHz based on load.

My conclusion is that, for some reason, the Athlon 5350 / Gigabyte GA-AM1M-S2H motherboard is incompatible with Ubuntu 18.04 and its derivatives (Lubuntu, Mint). Trying every flavor of PPA graphics drivers, plus forcing the CPU frequency, doesn't work. The little 5350 starts off at 2050 MHz in BIOS, but once in Linux it stays at 800 MHz no matter what I do (tried everything from forcing the performance governor, disabling cool n quiet, disabling c6 state, setting the min CPU frequency to 2.05 GHz, and explicitly setting the frequency). There seems to be many people having this problem for random flavors of AMD APU hardware in Ubuntu 18.04. I think I'm going to try an older version of Linux to see if I can get it working. It would be really cool to get some system efficiency numbers...at the moment this system is only drawing 25 watts at the wall (GPU removed).

[Theodore]

Odd. Have you checked CPU temperatures?
Sometimes, when there's an issue with the cooling, CPU gets throttled down.
You're getting numbers consistent with an 800Mhz CPU for sure.

[bruce]

I'd report this on the appropriate Linux support site. Whatever is making the setting of 800 GHz is probably understood by the Linux developers.

[Paragon]

So I tried Ubuntu 14.04, which was around when this motherboard was released, and everything works fine. Something in the later releases breaks the frequency scaling. I posted this saga in the Ubuntu forums and will see what they say...

[foldy]

Have a similar issue on AMD EPYC 7251 locked at 1.2Ghz which is too slow to feed a RTX 2080ti. But have no super user rights so no chance to fix the clock rate.