Can Network Card cause high ping?

[voltrex]

I have
windows 7 x64
VoIP Modem.
Arris Modem.
12Mb cable internet
ASUS P5K motherboard with built in Atheros L1 network card.

few month ago my downloading speed started to slow down from 12mb to ~9mb and even slow as 3mb
but upload speed remained high as usual.

i did:
- windows reinstall
- network drivers reinstalled
- firewall disabled
- antivirus removed and tried several same effect
- no viruses just few tracking cookies which were removed.
- modem changed to a new one.
- removed VoIP modem.
- called ISP support they couldn't help me either.
- changed LAN cable to a new one and still same effect.
- deleted every software/program which may connect and download from internet.

found out:
- if my computer connected to a modem, the ping on it extremely high as 400ms with 1% of packet loss
but if it is not connected to my computer the ping as low as 40-20ms no packet loss.
so the Modem is fine.
- when restarted the speed return to normal and slowly goes down again.
- when i do ping test to Ping -t 8.8.8.8 it goes from 90ms up to 130ms every 4 sec.

Qs:

can it be my Atheros Network card bad which cause high ping?

i can buy a new one for $20 TP-LINK .

 

[vizgl]

What is your response time and packet loss to local devices?
for example: have you setup a ping to your router or another local PC while pinging external hosts? It might help to compare the results.

Swapping the NIC out is the next logical step.

 

[voltrex]

I just ping another computer on my home network and ping range was from 95ms and up to 1108ms.
No packet loss detected.

but now my internet speed is normal as it should be with 5ms ping - was 15ms.

Can you suggest me what to do next?

EDIT - i have just realized that my computers stop responding when i downloaded large files on high speed.
and my when uploaded large files from my computer to my notebook via my router.
so my NIC may be broken. and not my windows.