[Jazz and Baroque]

Okay.... new topic

How should I choose between the PCI and PCIe versions of the SOtM USB cards?  Other than the fact that Playback Design DAC will apparently not work with the PCIe.  Playback Design is already too much $$$, so that is not a consideration for me. 

I have a suspicion that PCI has only USB 2, while PCIe has sockets for both USB 2 and 3.  Can't tell from the picture. 

My motherboard has sockets for both PCI and PCI Express 2.0 x16.  I think that means I have a choice here.  But the picture of the SOtM PCIe card shows a *plug* that is much smaller than the PCIe socket, although the description does call it a PCI Express interface.  Do I just push the small plug into the large socket ???

Thanks,
Mike

[kc8apf]

The card has a x1 connector. It can plug into any PCIe slot including longer ones.

[Jazz and Baroque]

But is the PCIe a better choice than the PCI card ?

[kc8apf]

PCIe is basically the same as PCI in terms of functionality.  It supports higher bandwidth which is important if you want to saturate USB3.

If you're worried about noise, PCI in a typical desktop computer runs at 33Mhz and uses a 32-bit parallel data bus.  That's a lot of single-ended signals that are switching at 33Mhz or slower (depends on if they actually transition from 0->1 or 1->0 or not for any given clock edge). 

PCIe uses a serial protocol that is striped over however many lanes the two sides negotiate.  Each lane uses two differential pairs (tx and rx).  The PCIe logic runs off a reference clock that is required to run at 100Mhz.  The SotM card uses a USB3 chip that has 1 lane and can run at either PCIe gen2 or gen1.  Gen2 will run the links at 5Gbit/s while gen1 is 2.5Gbit/s. 

I don't own either SotM card and have done no measurements but I'd expect the PCIe to be less noisy in the audio spectrum simply due to the higher frequencies it uses.

[Jazz and Baroque]

kc,

Thanks for the analysis.  Everything helps. 

Mike

[firedog]

Acc'd to Jesus at Sonore, the PCIe version is lower noise and sounds slightly better.

[Jazz and Baroque]

I sent a note to Sonore this morning.  They were very quick to reply and agree that the PCIe card is superior. 

"Michael
 
"Being that you will be using Window 8, you will not need the drivers that come with the PCIe card, although you will still need the firmware software that comes in the disc.
 
"I have listened to both cards extensively and I find the PCIe card to be way more Neutral than the PCI card.  Now mind you, our servers implement super clean power supplies including a specialty design linear power supply for the PCIe card so we are able to focus on the sound without the background comptuer noise.
 
"I would also recommend you purchase a SATA filter for the hard drive. The difference these filters make is indeed substantial in terms of soundstage and inner detail.
 
"Thank You,
Adrian Lebena, VP
Sonore"