I have noticed when Iam downloading at full speed of 1.8MB/s on Wifi or LAN there is high DPC/IR (Deferred Procedure Calls and Interrupt Requests) CPU usage - and when transferring files in or out to USB hdd.. i sometimes get pops & clicks in audio too - the CPU is a Turion 1.8Ghz x2 with 1Mb L2 cache and 2Gb of ram, DPC/IR can only be seen using Resource Monitor in windows 7 (type 'resource monitor' into startsearch) or using Process Explorer software, I dont know much about DPC/IR but as far as Im aware it handles errors or something like that and I was told it should never even go beyond 1% cpu usage - its more noticeable on laptops as these have CPUs that arent as powerfull as desktops and have wifi, it seems to be worse with wifi. it causes latency problems in windows too and things like audio playback get pops & clicks and windows & apps become sluggish.
What brought it too my attention was the CPU fan on my laptop was on all the time and windows seemed to be sluggish when I was downloading even though uTorrent was just using 3-5% CPU, I noticed the total at bottom of Task Manager seemed to be more than what would tally up in the window, it was when i used resource monitor that I seen it.
WiFi @ 1.8MB/s = 10-15% DPC/IR cpu usage
LAN @ 1.8MB/s = 5% DPC/IR cpu usage
Copying Files to USB HDD = 15% DPC/IR cpu usage (this test was odd as it was some time ago i done this one, but I remember it was either IN or OUT that had the increase, probably IN (and OUT was <1%) , I tried SDcard too and got varying results)
ive even seen it max at 40%
when downloading on wifi and
copying a file in/out too usb hard-drive at the same time...that is definitely not normal behavior another problem I have with my Atheros wifi card is that it peaks and troughs with the download speed and when it troughs the internet is slow almost unresponsive, but i dont think thats related and will start seperate thread for that
after searching the internet it appears that many others have this problem in Windows 7 and is related to their network driver
, many seem to have it much worse than me too.. I ran some program a while ago that monitors and tests to see whats causing it and it said it was NDIS.SYS which is the networking driver in Windows 7 (I think) - at first I thought it was related to Atheros Wifi driver but its not as ive seen many people with other drivers
, plus it happens on my LAN which is realtek
I think everyone suffers with this in windows 7 and that its a bug, those with powerfull CPU's and using LAN probably wont notice it , but those with sub 2Ghz laptops and Wifi should if they look for it.
Has anyone esle had this problem and if so found a fix for it?
I came across a post on MS TechNet of someone else with same problem and they were given a link to a MS page that had a fix for it .."hotfix for 20% decrease in performance when high network usage" - I downloaded it but it wouldnt install saying my system was not compatible or some bull...i had the x64 Windows 7 version too.. further on his post MS staff offered to have a look at it at cost of $300...needless to say that was the end of the post.
looking forward to replies