[zkms]

My reaction to PCIe gen 8 is essentially "Huh? No, retro data buses are like ISA, PCI, and AGP, right? PCIe Gen 3 and SATA are still pretty new...".

I wonder what modulation order / RF bandwidth they'll be using on the PHY for Gen8. I think Gen7 used 32GHz, which is ridiculously high.

[Dylan16807]

> PCIe Gen 3 and SATA are still pretty new...

That's an interesting thought to look at. PCIe 3 was a while ago, but SATA was nearly a decade before that.

> I wonder what modulation order / RF bandwidth they'll be using on the PHY for Gen8. I think Gen7 used 32GHz, which is ridiculously high.

Wikipedia says it's planned to be PAM4 just like 6 and 7.

Gen 5 and 6 were 32 gigabaud. If 8 is PAM4 it'll be 128 gigabaud...

[eqvinox]

I'd highly advise against using GHz here (without further context, at least), a 32Gbaud / 32Gsym/s NRZ signal toggling at full rate is only a 16GHz square wave.

baud seems out of fashion, sym/s is pretty clear & unambiguous.

(And if you're talking channel bandwidth, that needs clarification)

[kvemkon]

> > I think Gen7 used 32GHz, which is ridiculously high.

> 16GHz square wave

Is it for PCIe 5.0? PCIe 6.0 should operate on the same frequency and doubling the bandwidth by using PAM4. If PCIe 7.0 doubled the bandwidth and is still PAM4, what is the underlying frequency?

[guerrilla]

> baud seems out of fashion, sym/s is pretty clear & unambiguous.

Huh? Baud is sym/s.

[weinzierl]

Don't forget VESA Local Bus.