MacBook Air A1466 2017 Operating Very Slow

[ACS-Repair]

I'm hoping someone can help me with a 2017 MacBook Air A1466 820-00165 that is running very slow. This is a board that I picked up on ebay recently.
This is not being caused by a sensor issue. All sensors report normal operation and the fans run at normal speed. Geekbench gives me a single core CPU value of 124, when it should be closer to 400. I was unable to complete an install on the SSD without putting it into a different computer first.
The board appears clean with no sign of liquid damage. I have done a PRAM and SMC reset, and I have done a reflow of the SMC. I have inspected the board for missing components and they all appear to be in place. Apple Diagnostics says there are no problems. CPU is running at about 45 degrees even though it appears to have little load.
Very unique fault. Anyone have experience with something like this?

[mon2]

Re: MacBook Air A1466 2017 Operating Very Slow

https://www.it-tech.com.au/how-to-re...halfway-issue/

[ACS-Repair]

Re: MacBook Air A1466 2017 Operating Very Slow

Thanks for that @mon2. As a matter of chance I changed Q1920 but it was no better.
I have the voltages for the fets:

SPI_DESCRIPTOR_OVERRIDE =0V
SPI_DESCRIPTOR_OVERRIDE_L =3.3V
HDA_SDOUT_R =0V

These voltages appear to tell me that the ME is not disabled. Next, I will replace the EFI ROM to see if there is a corruption issue that is causing this.

[ACS-Repair]

Re: MacBook Air A1466 2017 Operating Very Slow

I loaded an EFI image with a clean ME and there was no change. This is a weird one... I hope I'm going to be able to sort this one out.

[dellxps15]

Re: MacBook Air A1466 2017 Operating Very Slow

option D or command D give u some error in diagnostic ?

generally when mac is slow mean bios problem or trackpad sensor problem.

fan spin slow of full spin?
without trackpad same behavios ? fan slow or full speed ?

[ACS-Repair]

Re: MacBook Air A1466 2017 Operating Very Slow

Apple Diagnostics showed there were no issues.
All sensors report good. A 2014 820-3437 works perfectly well in this top plate, battery, screen, etc. I'm just upgrading the logic board in this case.
Fans run at the normal speed. No high speed happening here. I've attached a screen grab of the CPU utilization in Intel Power Gadget.

The CPU appears to be running at near 100% utilization for about 5 minutes at startup. The CPU temperature never goes above 50 degrees, which I find rather strange. The CPU should get quite warm and the fans should ramp up to cool it down.

The previous owner noted that the board ran slow but I was sure it would simply be a bad sensor. not so lucky this time.

[piernov]

Re: MacBook Air A1466 2017 Operating Very Slow

.

[spidertnt]

Re: MacBook Air A1466 2017 Operating Very Slow

I have had super slow A1466 820-00165 caused by battery used from 2011 Air ....also some SSD from 2013 model will cause super slow [Toshiba] when used on 2015+

[ACS-Repair]

Re: MacBook Air A1466 2017 Operating Very Slow

Sorry @piernov, I'm not sure what you're trying to show me.
I did try another battery, again both working on the 820-3437 with no difference.

[piernov]

Re: MacBook Air A1466 2017 Operating Very Slow

60 W for an MBA CPU running at 600 MHz does not sound reasonable.

[ACS-Repair]

Re: MacBook Air A1466 2017 Operating Very Slow

No, you're right, that doesn't make sense when it's using a 45w genuine adapter. It may be an incorrect reading based on the fault. The 2015 MBA draws far less power by comparison.
You can see from the attached screen captures that the 2017 processor is running at only 0.5 - 0.6GHz. A comparison of a 2015 MBA shows it running at 2.47GHz average. This is the reason for it being slow but I have no idea why this would be the case. What can slow down the processor speed?

[piernov]

Re: MacBook Air A1466 2017 Operating Very Slow

If the system thinks it's drawing too much power it's gonna throttle down.

[ACS-Repair]

Re: MacBook Air A1466 2017 Operating Very Slow

Good thought. I'll take a look at the area around the ISL to see if there are any anomalies.
When the computer settles down after 10-12 minutes, the power draw usually comes down to 7-10 watts. I don't know how I get these strange ones...

[mon2]

Re: MacBook Air A1466 2017 Operating Very Slow

Measure the voltage to ground of each side of the current sense resistors.

Remove all power. Meter in resistance mode.

Measure the resistance directly at the ISL chip for the current loop legs. We had a case here on the forum where one leg was broken for the battery charge circuit. The ISL thought it was a too high of a current draw so it shut down the charge mosfets.

Perhaps the current sense resistor value no longer measures the schematic value.

[ACS-Repair]

Re: MacBook Air A1466 2017 Operating Very Slow

I checked the current sense resistors for the adapter and battery lines and they are all to spec (10/10, 2.2/0).
I changed the ISL just in case there was an issue with it, but unfortunately, no improvement. it still thinks it's drawing 58 watts.
I think this is a deeper problem. This may be an issue with the SMC or the processor / PCH. This board is very clean. No sign of liquid damage anywhere.

[ACS-Repair]

Re: MacBook Air A1466 2017 Operating Very Slow

After I let the computer settle for 10-12 minutes, the power draw settles down to more normal levels.
The power spikes to high levels on a regular pattern even though utilization is at a relatively low level. CPU temperature is dead steady in a fairly narrow range. That also is not normal.

[spidertnt]

Re: MacBook Air A1466 2017 Operating Very Slow

I'm hoping someone can help me with a 2017 MacBook Air A1466 820-00165 that is running very slow. This is a board that I picked up on ebay recently.
This is not being caused by a sensor issue. All sensors report normal operation and the fans run at normal speed. Geekbench gives me a single core CPU value of 124, when it should be closer to 400. I was unable to complete an install on the SSD without putting it into a different computer first.
The board appears clean with no sign of liquid damage. I have done a PRAM and SMC reset, and I have done a reflow of the SMC. I have inspected the board for missing components and they all appear to be in place. Apple Diagnostics says there are no problems. CPU is running at about 45 degrees even though it appears to have little load.
Very unique fault. Anyone have experience with something like this?

I have also seen super slow running 2014 / 2015 Airs ....clients running Mojave or Catalina.
Re-install of OS extremely slow .
fully booted Mac with Chrome launched does about 20 bounces before showing. Disk speed test runs normally . No high fan or sensor issues. lots of free disk space / No virus etc.

Installation of Big Sur resolve's problem

[ACS-Repair]

Re: MacBook Air A1466 2017 Operating Very Slow

I too have seen where some newer OSs will not load as well as older ones. In this case I am using Monterey, but loading Big Sur exhibited the same results. I had two other 2017s running Monterey with no problem so there is no reason this one won't either.
There is obviously some hardware issue that I need to resolve if I'm going to be able to use this logic board.

[dellxps15]

Re: MacBook Air A1466 2017 Operating Very Slow

the cpu has two sensor resistor. check those for any voltage leakage or drop.

edit: also when it's in idle it read 58 watt, but if u make cpu go high use, it still remain 58 watt ?

[ACS-Repair]

Re: MacBook Air A1466 2017 Operating Very Slow

I can check those resistors but I don't know which they are. Do you have the locations?
I believe the CPU operates at near 100%, but for some reason is only operating at 0.5-0.6 GHz. No wonder it takes so long to do anything.
I did a reading on a 2013 MBA that I created a thermal sensor failure on. In this case the fans speed up as expected. Results are similar to the 2017 except for the very high power draw. screen capture is attached.