Overclocking A NIC

[digitalgm]

Hey, has anyone out there overclocked a NIC? Does this make sense or is the bottleneck at the PCI bridge and not the NIC?


AAR

 

[RoadRuner]

hehe why overclock?

the best you'll see out of a pc is about 4500k/sec with 100 megabit ethernet over one protocol. You'll need to find a drive that can sustain writing at that speed then get back to me

 

[digitalgm]

Actually I have already seen in upward of 5MB/s

 

[spidey07]

new pcs can push a 100 megabit nic to 95% which is about 12.5 Megabytes a second or 12 megabytes of payload (data)

Depending factors:
NIC
Drivers
IP Stack
OS
Switched or shared
Latency between nodes
Speed of Disc

You guys must be hurtin to only get 4-5 megabytes a second.

As far as Overclocking a NIC my intel pro100+ runs fine at 37.5 mhz PCI

 

[digitalgm]

Well when I got the 5MB/s (today) both machines were on battery mode...


AdamR

 

[Peter]

Good 100-MBit NICs can pump an effective file data rate of up to 9 MByte/s - as long as both the systems can source and sink the data fast enough.

Note that overclocking is totally useless here, since the speed on the cable has to be exact on both sides of the cable, the oscillator requirement is six-digit exactness here. Forget it. And the PCI bus definitely is no bottleneck to that, so overclocking this side is entirely without effect.

The only approach to make LAN faster is to add more LAN. The AMD PCnet drivers for NT or W2K allow using up to four of their chips in parallel for 400 MBit/s.

Then of course you can add more buffers to each LAN chip - AMD's new PCnet-PRO chip can control up to 4 MBytes of its own local SDRAM for more effective buffering of incoming and outgoing data, to make best use of both the LAN and PCI side of the game.

Regards, Peter

 

[RoadRuner]

yah my point is the tcp stack and subsystem, and the general tcp protocol its hard to push more sustained for long periods of time.

btw i see 4500k/sec limit based on nt 4.0, which isnt the best of stacks, but its pretty good.


prolly a combo of hard drive, pci nic, pci bus, (quad xeon-550 dell poweredge), ftp protocol.

 

[Peter]

The secondary NIC I have here in my desktop NT 4.0 machine at work pumps up to 9 MByte/s when connected to the stuff on the lab desk.

While these are exclusive connections with only two nodes, the desktop machine isn't some miracle box: It has an Intel NIC, a Cyrix MII-300 on an old ASUS board, 128 MBytes of EDO RAM, and a slowish SCSI disk drive (remember, this thing is meant to WORK, and work it does). The stuff on the lab desk usually is newer, BX chipset based PIII machines with AMD LAN chips.

So anyone who can't reproduce speeds or around 7-9 MByte/s in benchmarking (use NT's Performance Monitor, and just move large files to and fro) should look for other system limitations like not enough RAM coupled with slow HDDs, other people on the same LAN segment eating bandwidth, non-busmastering PCI NICs (yes they exist) or PIO mode HDD drivers (if using IDE), or similar.

Regards, Peter