Atheros Wi-Fi ping issues

After the upgrade of the wifi adapter card in my ACER 7720G (changed the Intel 3945ABG with a more recent Atheros AR5B95) I've noticed a strange behaviour in the WiFi connection.
After a few ping sessions I've experienced very high ping variance (Jitter?). Ping time varies from less than 1 ms (as expected in my home network) to more than 400 ms.
I've tried to ping different devices from the Acer laptop but the results are substantially the same.
I managed to ping from a desktop connected via Ethernet and obtained the same values, while other devices respond in few istants (< 1ms).
This behaviour happens regardless of the positioning of the laptop, even if I stay very close to the access point.
I checked with other wifi connected equipments and I didn't get the same results: ping time variance is very low, varying from <1ms to few ms (1 to 3 ms, pinging with -t parameter).
Nevertheless, I also tried to ping while connected via Ethernet and. obviously, ping time is constant and limited to fractions of millisecond.
This leads me to concentrate on the Atheros adapter and in its configuration.
Could anybody suggest me how to lower the Jitter?

Thanks in advance.

 

I moved it to Networking forum and added a title.
If you think it does not fully reflect the issue PM me and I'll change it to wherever you think it should say.

 

Effectively I was wondering if I was doing right...
I'm sure you moved my message in the right place. Sorry for my improper posting.

 

Solved.
I acted as follows.

1. downloaded TCPOptimizer and applied optimized settings .
2. Modified Transmit Buffers =512 and Receive Buffers=512 on Atheros driver Advanced settings
3. Rebooted

Now pinging other network devices is fast (<= 1ms) and stable (max 2ms for router and repeater, 4 ms for PCs and 6 ms for printer).
Pinging Aruba site (italian cloud provider) gives 17 ms with 1.5 ms jitter on my VDSL 50mbps connection against the over 80 ms with high jitter (15+ms) in the previous configuration.
Hope this can help.