02-03-2015 07:18 AM
Hi, I have a brand new Edge E540 with a freshly installed Windows 7 Professional x64. I have all the newest drivers, but when I play audio I experience dropouts, which I suspect to be due to high DPC Latency. According to Latency Mon the main culprit is ndis.sys, closely followed by my USB drivers (iusb3xhc.sys, or if I uninstall that, USBPORT.sys). There are a few others with much higher latency than they should have, as you can see here:
Disabling Wi-Fi gets rid of ndis.sys which helps quite a lot, but I'd quite like to be able to listen to music and use the internet at the same time. There are two different WLAN drivers on the Lenovo website and I've tried both but to no avail.
I've also tried all the standard changing Power Management options and that kind of thing, and am at a complete loss at what to do next.
02-06-2015 03:31 AM - edited 02-06-2015 03:34 AM
This is odd, i never had that problem on my machine... E540, core i7 4702MQ ...
Try disabling USB3.0 in the bios, and put it in 2.0 mode and check it.
USB 3.0 has lot's of problems under win 7 ...
I used windows 7 only for two weeks on my laptop, because i bought 8... anyway on windows 8, everything is fine.
Also what kind of USB devices do you have connected. Because some device could be USB3 incompatible or with bad USB cable/connection and could be flooding the USB controler.
Usb 3 is way more capricious than 2.0, especially with longer than 3 meters cables.
P.S. Oh i forgot to mention that there used to be reported some "cracking" noises with the older bios versions, so also try updating the BIOS to the latest.