Low CPU load miniPCI-E wifi card

[9lives]

Hi.

I have a laptop which originally came with an Intel 802.11bg (4000 series, can't remember exactly which one). I wanted to upgrade to 802.11n so bought an Intel 6200 card, but the CPU load performance is terrible!

My laptop has a dual core LV Core 2 CPU, which is adequate for most stuff but seems to be crippled by this card. It is noticeable even when browsing, let alone doing a file transfer. The old card was fine, and a couple of different Ralink USB cards are fine as well. Apparently the 6200 is some kind of crappy Winmodem...

Anyway, now I'm looking for a better card, but there is almost no information on the net about the CPU load created by different wifi chipsets. Can anyone recommend a good card or chipset to look for? The laptop only has two antennas if it makes any difference. It also only has two USB ports so I don't want to rely on a USB card if possible, internal miniPCI-E would be best.

 

[stevech]

I suspect there's something other than WiFi hardware/driver at fault here. Installation/configuration problem. Never heard of high-CPU usage by a WiFi PCI card.

 

[TonyH]

Wonder if that laptop has newer BIOS available. WiFi card is independent
from CPU. How much memory do you have on that laptop? What is OS?
Winmodem(software modem) is known trouble maker. Disable it from device manager.

 

[9lives]

Hi guys.

It is a Panasonic Let's Note CF-Y7 running Windows 7 x86. 2.5GB RAM and an SSD for storage. As I say the old card and USB cards all work fine, it is just that Intel 6200 that sucks.

The laptop's modem is already disabled in the BIOS, and it is the latest version. All I meant was that the 6200 seems to offload a lot of the work to the CPU, causing the machine to be slow. In the task manager I can see that the kernel is taking up a lot of CPU time when the card is active, which is the driver. The driver is also up to date, by the way.

The Atheros 5008 seems to be a good card. Unfortunately I can't find any info on CPU usage.

 

[tipstir]

Run as the Admin using Dos Prompt window or you can type this into bat or cmd file Note this is for Windows 7 or Windows 8 ONLY! XP does it a different way.

netsh int tcp set global chimney=enabled


batch file:
Run as Admin when you use the below files.
notepad copy the live above to notepad and past it in

@echo off
netsh int tcp set global chimney=enabled
pause
exit

or

Run as Admin when you use the below files. cmd file:

notepad copy the live above to notepad and past it in

netsh int tcp set global chimney=enabled

pause
exit

or command prompt run as Admin

Reboot your laptop.

This process above will off load the network task on your dual core CPU to NPU on the NIC.

 

[9lives]

Thanks tipster, but it didn't help. The card doesn't seem to support TCP Chimney offload. There is no option to enable it in the driver, and even after enabling it from the command line netstat shows that no new connections have been offloaded.

Reading a bit about it apparently hardly any wifi cards support Chimney Offload.

So I have another question: Would an Atheros 5008 card with three antenna connectors work okay with just two of them connected? My laptop is very compact and I doubt I could fit another antenna in.

 

[stevech]

Most all WiFi routers and client devices implement the "top half" of the MAC layer protocol in the CPU. The bottom/lower level of the MAC is timing sensitive and is in firmware and partially hardware with the PHY.

Even so, it's a tiny CPU load.

When the CPU load is high and you suspect the WiFi, have you used windows task manager, processes view, sort by CPU usage, to see who's hogging?

 

[9lives]

When the CPU load is high and you suspect the WiFi, have you used windows task manager, processes view, sort by CPU usage, to see who's hogging?

I have, and it is the kernel that is hogging all the time. You have to enable kernel times before you can see this. The driver executes in the kernel, so this strongly suggests that it is the card's driver.

As I say, other cards and the original 4000 series card were all fine. I might try an Intel 4965 instead. The Atheros is tempting but I can't find any information on how well it works with only two antennas, while the 4965 is known to be okay. The downside with the 4965 is that it only supports 130Mbps on 2.4GHz, and my router (ASUS N16) doesn't do 5GHz.

 

[9lives]

Okay, Intel 4965 arrived and fitted. CPU consumption reduced to similar levels to the USB adapters. I added an extra 3rd antenna while I was at it.

The Intel 6200 is a POS, the Winmodem of wifi cards. Raw throughput was good but the load on the system was ridiculous.

 

[stevech]

I suppose some vendors do sloppy drivers, or put too much MAC functionality into the CPU drivers instead of on the WiFi hardware signal processor. The latter would reduce recurring hardware cost.

Ideally, the vendor would correct/update the driver- unless it can't be done because of the above.

 

[sfx2000]

Okay, Intel 4965 arrived and fitted. CPU consumption reduced to similar levels to the USB adapters. I added an extra 3rd antenna while I was at it.

The Intel 6200 is a POS, the Winmodem of wifi cards. Raw throughput was good but the load on the system was ridiculous.

Welcome to what we call SoftMAC - the intel card has the baseband/RF in hardware, but the MAC layer is in software.

Some HW/SW combos are better than others - Intel has made some good steps, as they have a hybrid MAC layer in their driver - depends on what ICH is being used.