PC won't link at gigabit?

[Kremlar]

I have a PC that absolutely won't link at gigabit speeds to my Netgear 48-Port switch. All other PCs on my LAN are fine at gigabit, network jack is fine, cable is fine - it appears to be some sort of compatibility issue between the NIC in the PC and my switch.

If I take a small 5-Port Linksys switch and connect it between my PC and the Netgear switch, it syncs fine at gigabit and I'm able to transfer at gigabit speeds (or close enough) around my network. I'd prefer not to leave the Linksys plugged in if possible, however, if I can find a workaround.

Netgear switch has the latest firmware installed, and PC has the latest Marvell Yukon gigabit driver installed.

Any tips/tricks on getting these things in sync? Perhaps some property setting on the NIC driver?

Thanks

 

[JackMDS]

Try a PCI NIC to make sure that the Onboard NIC is Good.

 

[Kremlar]

Unfortunately it's a SFF PC, so no add-on slots.

I do get a good gigabit connection with a Linksys switch between it and the Netgear switch.

 

[her209]

Have you tried contacting the manufacturer of the motherboard/NIC to see if this is a known problem?

 

[xSauronx]

Originally posted by: Kremlar
Unfortunately it's a SFF PC, so no add-on slots.

I do get a good gigabit connection with a Linksys switch between it and the Netgear switch.

are you using the same cable to test that, or a set off different ones?

 

[Kremlar]

Tried different cables, same issue.

 

[spidey07]

Sounds like a cabling problem. Some switches will swap tip/ring to correct it which it sounds like what the linksys is doing.

 

[Kremlar]

Definitely not cabling. Multiple Cat6 and Cat5e patch cables, same issue. Other PCs in its place work fine. I've spent hours bouncing things around. Issue is intermittent too - sometimes it will link for an hour or 2, then suddenly disconnect.

Perhaps it's a flakey NIC. Very strange...

 

[spidey07]

Are these store bought patch cables? Not getting link is an immediate indication of a physical layer problem (cabling)

 

[Kremlar]

Yes, all store bought.

Again:

- new cables, same problem
- different PC, works fine
- lock down at 100Mbps, original PC works fine

Seems to be something specific about this NIC linking to this Netgear when set to auto or locked down at 1000Mbps.

 

[spidey07]

In that case I'd look at flow control (only applicable to 1000 Base), that would cause you to not get link. Probably a bug in the switch software or drivers if that's the case. It happens. I'd call netgear or research bugs with NIC drivers. Just because they are latest doesn't mean there aren't bugs.

 

[Kremlar]

Just wanted to followup - disabling flow control on that port of the switch seemed to fix the issue. Thanks for the tip.

 

[Kremlar]

ANOTHER followup! After a couple of days with flow control disabled, PC was once again dropping the LAN connection. I dropped it back to 100, and again it's stable - so it's going to stay at 100.

 

[theevilsharpie]

You stated that you updated the firmware on your Netgear switch, so I assume that it's a managed switch. I don't have much experience with Netgear managed switches, but if they support debugging (or some other type of verbose logging), check it to make sure that it's not disconnecting the NIC because of excessive errors link errors. Given my prior experience with integrated Marvell NICs, it wouldn't surprise me if the NIC was malfunctioning.