Very Slow Internet Connection - Realtek NIC

I have two desktops set up in my place, and they both act very differently when it comes to my internet connection. They both have very similar hardware setups, which include overclocked i5 750 processors, 4 gigs of GSkill RAM, and Gigabyte P55 mobos.

They're both ethernet-connected to a LinkSys WRT54G router. The system closest to the router is the one giving me a painfully slow internet connection. The only way I can describe the behavior is by saying that web pages load content in one-second increments, and pages take anywhere from 8 - 20 seconds to fully load. On my other system, pages are fully loaded within 3 seconds. The other behavior example I can give is related to typing any information in Chrome's URL/search bar. When typing anything into the fast system's bar, the auto-fill (not sure of the feature's actual name) feature immediately fills in suggestions, while the slow system's bar doesn't auto-fill for a few seconds.

Both machines' motherboards have Realtek NICs in them, and I've read a bit on the web about it. Pardon my ignorance, but are they both supposed to show a 1000Mbps second connection when I check their respective Properties in the network sharing area? They both currently show as being a 100Mbps connection. Then again, one is running at the right speed, so I'm not sure that's the problem. I've tried loading a few drivers for the NIC, but that doesn't seem to help. I've disabled Green Ethernet, which is a Realtek feature. I changed the link speed to full-duplex at 1000Mbps, which didn't make a difference.

I'm not sure if this tells me anything at all, but, when running speed tests at speedtest.net, my fast machine shows a 5ms-13ms ping range with an approximate 20Mbps download speed, while the slow machine shows a 25ms-35ms ping range with similar DL speeds.

I was also wondering if it had anything to do with the RAM not being set correctly, and I even traded out sticks to see if it would make a difference. Here's the really strange part: There have been two separate instances where the web became as snappy as it should be, and, each time, it lasted for a few minutes. The second time, once I rebooted my system, it went back to being lame.

I'm desperate for help, so any suggestions on what I should try are much appreciated.

Thanks in Advance!

PS - Both machines are running Windows 7 Pro.

DMHolt57 said:

both nics are 100 mbps with direct ethernet. I would remove the nic from the device manager, then reboot the computer, Win7 should pick it up and apply the proper settings, it that doesn't solve it, could be a hardware problem...

Thanks for the suggestion, DMHolt. Unfortunately, deletion/re-installation of the NIC in the Device Manager wasn't successful. Is there any way to test the NIC for trouble outside of pinging it? Should I have a closer look to see if anything might be loosely connected?

It's been several months since I revisited this problem, but I think I've run the gamut of everything I can do, and I wanted to see if any of you have any further suggestions. Here's what I've done:

1) As suggested above, I removed the onboard NIC from the Device Manager and let Windows find the settings/drivers on reboot
2) I purchased a new PCI NIC and disabled the onboard NIC, but the new card showed the same behavior
3) I tried different Cat5e/6 cables
4) I've tried different BIOS for the mobo to see if that would make any difference (Gigabyte P55 UD2)
5) I tried different sticks of RAM
6) I've overclocked the CPU/set CPU to default settings

I'm out of ideas, and I'm wondering if I simply have a bum motherboard or something. It's just strange that my other desktop with a p55 Gigabyte totally hauls a** with regards to surfing and such. Should I try reloading the OS? This just doesn't make any sense. Any further suggestions are appreciated.

TiA!