Hi.

Windows 1909 x64
x470
Titanium HD

When ALchemy is used, do EAX effects come from the actual SB circuitry in this case, or the presence of the card in a system just signals the driver to enable EAX software emulation?

ALchemy converts the DirectSound calls to OpenAL and there's no clear information about whether or not it's done in hardware mixing, via the soundcard DSP or the host CPU. Contrary to popular belief, Windows 10 DOES support hardware accelerated audio and EAX could be resurrected with some effort, but Creative simply won't write drivers that allow use of it, as they have abandoned it and don't seem to have any real development teams these days, to handle that sort of thing.

Since you had concerns with lossless audio, I can recommend you the card I use - Auzentech X-Fi HomeTheater HD. It has the creative x-fi chip with eax5 and cmss3d and everything, but it also has pretty high-quality components, and a real rarity for sound cards - a hdmi output! You can get lossless 7.1 audio to your receiver out of this thing 😀 No drivers for the latest few feature updates of win10 tho, but it can work on an older version such as 1607 LTSB, and of course works perfect on win7, vista and XP.

There was also that Onkyo Wavio PCI-E card, basically same as Titanium HD but better.
Good luck finding one though.
If you use Creative cards (Titanium HD or newer), they allow for op-amp replacement, and there are many topics over the Internet where people do it with great results.

I'm looking for the Onkyo myself to complete my collection, but this auzen is the only x-fi to have a hdmi output, so it's safe to say its the best of the x-fi cards, as long as you would make use of the hdmi for lossless 7.1... sad to say I'm not using it yet as I don't own a good receiver, so I'm just using the 3.5 analog outputs for now