I'm trying out Windows 7 RC x64 on my computer and noticed it was showing outrageously high CPU usage at idle. Of course, first stop was task manager which points a finger at "System Interrupts". A quick Google search led me to suspect hardware. Through trial and error disabling components, I found the culprit: Marvell Yukon 88E8001/8003/8010 PCI Gigabit Ethernet Controller
Here is task manager with it enabled, system at idle. All cores are showing usage, but cores #1 and #3 are totally unacceptable:
Here is task manager after disabling the Marvell LAN. CPU usage immediately flatlines on all four cores:
Just to verify, re-enabling the LAN causes CPU usage to go crazy again:
I've tried updating drivers, using many variations of both Microsoft and Marvell drivers with no luck. Is anyone else seeing this problem with the same Marvell LAN controller? Does anyone know of a fix?
I cannot verify whether the LAN is non-functional as I don't use a wired connection. I can just leave it disabled but having this kind of workaround bugs me.
Microsoft does have an official Windows 7 RC Support Forum located here http://tinyurl.com/9fhdl5 . It is supported by product specialists as well as engineers and support teams. You may want to check the threads there for additional support.
Since you're not using the adapter, it's better to disable it anyway... it's taking up resources that could be freed up for other uses. One troubleshooting step I can suggest is to plug it into a router and see what happens. It's probably gobbling up CPU cycles attempting to obtain an IP address. Most likely a bug that will be fixed with newer drivers or when Win 7 goes RTM.
I had a similiar issue with W7 64B Pro on a AMD Phenom II using an on board GeForce 8300 with Nvidia chipset. I had to reload all drivers for the Mobo and that reduced the high usage, but not all of it. I finally discovered the onboard video was draining the CPU resources during system interrupts which were struggling to keep up with W7 rich graphic content. I reset the color from 32bit true color to 16bit colors and the CPU usage is now 2-3% on full load. Of course now my video is not working, but I am moving to a 1gb Geforce 9600 video card ($49 at Tiger Direct on sale now) to handle the graphics. You may want to check your graphics and upgrade accordingly.
I had the same problem with "Marvell Yukon 88E8001/8003/8010 PCI Gigabit Ethernet Controller"
after updating the driver i played with parameters in the advanced tab of the driver (in the device manager ,network adapters).
and the probleme stoped/
try to limit the "max IRQ per sec" to 1000 insted of 5000.
I have a Qualcomm Atheros AR8151 PCI-E Gigabit Ethernet Controller (NDIS 6.20)
I was wondering if the max Irq entry in the advanced properties could be lowered and would I see a performane gain with anything? It is currently set to 5000. I heard that it could be lowered to 1000. I just want to make sure that it would be okay to do that.