32 bit vs 64 bit land card

[U3002083]

What's difference between 32 bit and 64 bit lan card.

[raulfg3]

One use PCI x32 (normal PCI)

Other use PCI x64 (PCI-X)

Better if use PCI-e NIC (PCI-express)

[U3002083]

What if they say 32 bit gigabit lan card

And 64 bit gigabit lan card.

What are advantages of 64 bit over 32 bit if both are gigabit card.

[00Roush]

The 64 bit card can transfer more data at the same bus speed. Standard PCI slots on most motherboards are PCI 32 bit slots that operate at 33mhz. Throughput is max of 133 MB/sec. PCI-X 64 bit slot at the same 33mhz can do 266 MB/sec. Just to note PCI-X slots typically are only found on server motherboards. If you don't have PCI-X slots there really is no advantage to getting a 64 bit card.

On the topic of 32 bit PCI vs 64 bit PCI-X network cards... I happen to have a Intel network card that is PCI-X. I have found that I can install this card in a regular PCI slot even though it is larger than the slot. Card supports PCI/PCI-X at 33 MHz or 66 Mhz so it works just fine however it is limited to 32 bit operation in the regular PCI slot.

00Roush

[U3002083]

00Roush nice answer. thanks

so you mean a 64 bit gigbit lan card speed will be 2 gigbit .

[raulfg3]

so you mean a 64 bit gigbit lan card speed will be 2 gigbit .

NO

[00Roush]

To expand further... gigabit card will only do just gigabit even if 64 bit PCI-X. Gigabit max speed is about 125 MB/sec in each direction. So technically 32 bit PCI (133 MB/sec shared by all PCI devices) can do full gigabit but in real world max is about 100 MB/sec in one direction. 64 bit PCI-X can support double that which means a gigabit card can send and receive 100+ MB/sec at the same time.

00Roush

[Lee Sharp]

And keep in mind that on a shared buss, that gigabit of data has to come from somewhere also on the same buss. So you end up splitting and getting 66MB to the nic, and 66MB to the drives... So less than the gigabit the car can do.

[Andy22]

And keep in mind that on a shared buss, that gigabit of data has to come from somewhere also on the same buss. So you end up splitting and getting 66MB to the nic, and 66MB to the drives... So less than the gigabit the car can do.

mhh whats the scenario for such a "shared buss" split? Is this if u use a separate pci raid/sata controller, instead of the onboard sata?

I have a old DGE-528T 32bit pci card and using samba i can reach 100 MB/s up/down speeds from the sata ports?

Thx
Andy

[b0ssman]

yes but you prob have an onboard lan card and a motherboard with pcie. there the lan is not sharing the the bandwidth with the pci bus.
modern mainboard do not have a native pci bus anymore.
there the pci bus is using one pcie lan using an pci/pcie bridge chip.

the shared bus mostly applies to older chipsets which do not have pcie.

[Andy22]

yes but you prob have an onboard lan card and a motherboard with pcie. there the lan is not sharing the the bandwidth with the pci bus.
modern mainboard do not have a native pci bus anymore.
there the pci bus is using one pcie lan using an pci/pcie bridge chip.

the shared bus mostly applies to older chipsets which do not have pcie.

I do, but as noted i installed a old "DGE-528T 32bit" pci card in a pci slot, since i had some WOL problems with the onboard card.
Since i can still reach 100MB/s in real world file copy operations under Win7 using 7k Jumbo frames i was wondering when such a "shared pci" scenario actually occurs. So as u pointed out if its using a actual bridged pci-e lane, than this pci limit does not apply on modern boards even if u use a old pci card?


Thx
Andy

PS: The DGE-528T has a crappy realtek chip, but i guess under windows they did some driver "magic" to make it run fast, without problems.

[b0ssman]

it depends on the chipset

look at this picture of an old 850e chipset

http://www.thg.ru/cpu/20020506/images/i850e-block.jpg

it shows that the pci bus has 133 mb bandwidth

the south bridge to the northbridge has 266 mb

the ide channel here is independant of the pci bus bus still has to use the same southbridge/northbridge link.

however the pci devices could transfer data between themselves without going via the southbridge/northbridge, but that was seldom used.