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got an old laptop a Dell Inspiron E1505 with an Intel 5300 wifi card. But when this thing hits full bandwidth (about 100mb/s on 5ghz N), cpu usage hits about 100% on one core (C2D T7200). Happens in Windows with built in drivers and the latest drivers on Intels website, I thought this might have been a driver problem... but it also happens on Linux with Fedora 31 using the open source driver.

Any idea what is going on? Didn't think wifi would push CPU that much. Have no frame of reference on whether this is normal for hardware this old, on my much newer Inpiron XPS 15 and Surface 4 Pro wifi contributes to negligible CPU usage on 5GHz ac....

seeker010 wrote:

got an old laptop a Dell Inspiron E1505 with an Intel 5300 wifi card. But when this thing hits full bandwidth (about 100mb/s on 5ghz N), cpu usage hits about 100% on one core (C2D T7200). Happens in Windows with built in drivers and the latest drivers on Intels website, I thought this might have been a driver problem... but it also happens on Linux with Fedora 31 using the open source driver.

Any idea what is going on? Didn't think wifi would push CPU that much. Have no frame of reference on whether this is normal for hardware this old, on my much newer Inpiron XPS 15 and Surface 4 Pro wifi contributes to negligible CPU usage on 5GHz ac....

https://www.dell.com/community/Latitude ... -p/7462499

As a temporary solution I decided to disable the Intel proset wireless services. I expected that I could not use Wifi anymore. To my surprise Wifi is still working. After a reboot, the Proset services are not switched on again, wifi is still working and CPU usage (and the fan noise) is down to normal again.

So possibly a software issue. Disable Intel's PROSet services.

I have always recommended using just the base intel driver without the proset services installed.
Also use windows to manage the wireless networks.

That should fix most of your weirdness.

sigh... guys I said I used both the built in drivers for Windows and the ones from Intel. This also happens in Linux as well so not a proset issue.

looks to be an interrupt issue though, at least in Linux. I see the irq/28 line taking up a lot of resources during downloads. not sure how to proceed from here.

If you are seeing an interrupt using a lot of resources the only thing I can think of suggesting is to make sure that DMA is enabled in the driver. Otherwise it would be in some sort of polling mode for data copying and would use a lot more CPU time and would be interrupt driven. From my embedded days, interrupts where processed by a number of CPU types on core 0 so it would only load one of your cores. I don't remember Intel specifically handles interrupt processing.

That said it seems odd that something like DMA would be disabled in both Linux and Windows unless it is just saved in the wifi hardware and read by the driver instead of configured by the driver on start up.

Check BIOS options. Might find something of use there.

Does it happen when downloading over wired LAN?