3 ms·

PCIe gen3 is nearly a GB/sec in each direction per lane (actual bandwidth obviously less). Which is nearly enough to get to line rate with 10Gbit ethernet, part

PCIe gen3 is nearly a GB/sec in each direction per lane (actual bandwidth obviously less). Which is nearly enough to get to line rate with 10Gbit ethernet, particularly if TSO is employed to remove the framing/etc overhead. Getting 750MB/sec out of a 10G interface because its constricted by PCIe is a lot better than getting 220MB/sec out of 2.5G. Consider the difference when running a VM image from a NAS. Further, the point with the multimode 1/2.5/5/10 phy's is they do line quality detection and downgrade. So you plug in cat5, and it downgrades to 2.5 if the line quality is bad. Someone runs a 10 foot cat6A cable they are going to get the full speed. But in actuality, as I said on this board before, 10G requires cat6a for 200 meter runs. If your in a house, small office, etc where the runs are 5-10 meters or less cat5e works just fine. I've seen switch vendors mention that quality cat5e can be good up to 45M, which is farther than cat8 is specified for 40GbaseT. It just looks like more product segmentation since the 10GbaseT spec has been around for about 15 years now. edit: When it comes to UTP, the frequency response and cross talk specifications effectively end up being per foot. So the line attenuation and noise increases with cable length until it falls below the threshold required to reconstruct the signal at the far end given a standard compliant part. The length and cabling requirements also include the possibility of loss from additional wall jacks or patch panels. So many of the bulk cat 5e cable packs were sold for a long time as 350mhz (or similar) which in name is better than basic cat6 at 250mhz because its actually pretty hard to screw up the twist/etc requirements of the cable. The problems happen when it is poorly terminated. So the whole thing ends up being a bit of a crapshoot whether any given cable works to specification (most aren't) but because they are far below the maximum line lengths it never matters. Plus, in the decade(s) since the specs were initially created semiconductor advances have allowed advances in the receiver sensitivity and efficiency of the drive signal. Meaning if one went back at this point and tweaked the 1G spec its quite likely that the max transmission lengths could at least be doubled due to specifying it with cat5e and tighter margins. This is also what allows 10GbaseT SFP's today, which weren't initially possible (that and mandating that they aren't compliant to the full 200M).

jeffbee 6y ago
It's not product segmentation. They cut the NIC price to $2 and increased the speed by 2.5x. This is really the only part of the platform that is dramatically faster than it was two years ago. Most of the AMD motherboards are coming with 1gbps ethernet, no matter how many nonsense words are in the product name.
- StillBored 6y ago
  The pricing difference is part of the product segmentation, because 10G+ has been reserved for "enterprise" parts despite not being much different at this point. There are ARM SOC's out there, where the bare SOC is in the $40 ballpark and comes with 10G integrated. 10G isn't inherently more expensive, its just been a decision not to repeat the "mistake" that was the 100-1G transition where the price went from $$$$ to 1/10$ in the space of a year.
  - jeffbee 6y ago
    I don't understand what we are talking about. None of the CPUs in this article have integrated NICs. The NIC is a little pea-sized peripheral device on a PCIe port. If the motherboard makers thought anyone needed a desktop platform with 10gbe, they'd ship that. But 10gbe controllers cost a lot of money and draw a lot of power, and take more pci-e lanes. I think they are banking on the idea that people who want it will be happy enough with expansion cards or thunderbolt peripherals.
    - StillBored 6y ago
      I was mixing cpu+chipset=arm soc. A 10G port takes the same PCIe lane as a 1G port, particularly if you have PCIe gen4+ or are willing to potentially lose a bit with gen3. Similarly with power, EEE doesn't use the power if its not needed. Which for users on short runs, or with 1G switches the power utilization will be the same as a 1G port. And given that we are talking 200W parts, a watt or two for 10G isn't going to be missed. And probably more of the motherboard manufactures would put 10G nics on board if there weren't a dearth of 10G pci nic chips from manufactures not already selling PCIe nics as high margin products. AKA intel selling its 10G part for more than the rest of the parts on the motherboard is going to keep motherboard manufactures from putting it on every motherboard. Its sort of been a game of chicken, which will explode violently when the patents expire and a company like etron or asmedia starts producing them. (both of which have shown plenty of inhouse capability for producing high speed phy/etc interfaces).
      - 6y ago

jeffbee 6y ago

It's not product segmentation. They cut the NIC price to $2 and increased the speed by 2.5x. This is really the only part of the platform that is dramatically faster than it was two years ago. Most of the AMD motherboards are coming with 1gbps ethernet, no matter how many nonsense words are in the product name.

StillBored 6y ago
The pricing difference is part of the product segmentation, because 10G+ has been reserved for "enterprise" parts despite not being much different at this point. There are ARM SOC's out there, where the bare SOC is in the $40 ballpark and comes with 10G integrated. 10G isn't inherently more expensive, its just been a decision not to repeat the "mistake" that was the 100-1G transition where the price went from $$$$ to 1/10$ in the space of a year.
- jeffbee 6y ago
  I don't understand what we are talking about. None of the CPUs in this article have integrated NICs. The NIC is a little pea-sized peripheral device on a PCIe port. If the motherboard makers thought anyone needed a desktop platform with 10gbe, they'd ship that. But 10gbe controllers cost a lot of money and draw a lot of power, and take more pci-e lanes. I think they are banking on the idea that people who want it will be happy enough with expansion cards or thunderbolt peripherals.
  - StillBored 6y ago
    I was mixing cpu+chipset=arm soc. A 10G port takes the same PCIe lane as a 1G port, particularly if you have PCIe gen4+ or are willing to potentially lose a bit with gen3. Similarly with power, EEE doesn't use the power if its not needed. Which for users on short runs, or with 1G switches the power utilization will be the same as a 1G port. And given that we are talking 200W parts, a watt or two for 10G isn't going to be missed. And probably more of the motherboard manufactures would put 10G nics on board if there weren't a dearth of 10G pci nic chips from manufactures not already selling PCIe nics as high margin products. AKA intel selling its 10G part for more than the rest of the parts on the motherboard is going to keep motherboard manufactures from putting it on every motherboard. Its sort of been a game of chicken, which will explode violently when the patents expire and a company like etron or asmedia starts producing them. (both of which have shown plenty of inhouse capability for producing high speed phy/etc interfaces).
    - 6y ago