No. There are other options.
If you want older PCIe you can check Xonar DX/D2X, X-Fi Forte is also PCIe.

I'm guessing you simply want upmix to 4.1 from 2.0 stereo to work, right ?

There was a Xfi titanium HD for the audiophiles. It's not early though.

I'm pretty sure Titanium HD is stereo only... unless your speakers utilise SPDiF.

Yes I only want the "speaker fill" option to work again.
( MSI Z390 Gaming Plus= integrated Realtek ALC892 does not have speaker fill and sounds bad on 4.1.) 😢
- So that all 4.1 speakers are filled with the same equally sounding music.

Do those 2001 speakers have multi drivers and a crossover ? Just curious because my 1990's Infinity's have a crossover and the caps went bad making them sound dull and lifeless. Just a thought...

No works 100% in Win7 and with old PCI sound cards.
Then I upgraded to Windows 10 bought a new PCIe only motherboard MSI Z390 Gaming Plus which has a integrated Realtek ALC892. +I tried also Sound Blaster Z.

Now waiting for X-Fi Titanium and Xonar Phoebus 7.1 to arrive.
Wondering if anyone else is using 4.1 speakers with Win10 ?

Sound quality mostly depends on the DAC the card uses.
A DSP will take some load off the CPU but stereo -> 4.1 surround upmix quality depends on the software used. With fast modern CPUs audio has very little impact on system performance, that's why a specialised DSP isn't really important anymore.
Have you considered using a PCIe -> PCI slot adaptor? If you like the way your old card sounds and how surround upmix is handled by its driver maybe that's your best bet. 😎

Do those PCIe-PCI adapters work ?
- I looked those adapters one night.

Then I was thinking that if my 2002, FPS1600 4.1 SoundWorks speakers aren't compatible with Win10 anymore. Don't know if there are any hardware differences compared to modern sets ? These below are probably the only 5.1 modern speaker sets available today:
-Logitech Z506 5.1
-Logitech Z906 5.1
-Creative Inspire T6300 5.1

user33331 wrote:

Do those PCIe-PCI adapters work ?
- I looked those adapters one night.

Generally speaking yes, they work. They feature a PCIe->PCI bridge chip (which is exactly how most current motherboards incorporate PCI) plus often some sort of power delivery. But sometimes there are problems with motherboards/UEFI not fully supporting the chips or DMA/IRQ on them. The only way to know for sure is to try. 😵

user33331 wrote:

Then I was thinking that if my 2002, FPS1600 4.1 SoundWorks speakers aren't compatible with Win10 anymore. Don't know if there a […]
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Then I was thinking that if my 2002, FPS1600 4.1 SoundWorks speakers aren't compatible with Win10 anymore. Don't know if there are any hardware differences compared to modern sets ? These below are probably the only 5.1 modern speaker sets available today:
-Logitech Z506 5.1
-Logitech Z906 5.1
-Creative Inspire T6300 5.1

As long as your speaker set is connected via audio cables (no matter wether analog or digital) and does not have some sort of built in sound card OS compatibility isn't an issue. Your sound card has to have proper drivers for your OS.
Objectively your speakers probably don't have the best sound reproduction. Still sound reception is very subjective and wether you like the sound of your speakers heavily depends on preference. If you're used to the speakers you're currently using and like how they sound there's no need to upgrade.

Back in the early 2000 these speakers where the holy grail. Like best of the best. 😊
Cambridge SoundWorks FPS1600 4.1 FourPointSurround.

- What modern speaker 5.1 set sounds same or better than the old Cambridge ones ?

* I have in a another PC a pair of Creative GigaWorks T20 Series II but they sound kind of bad worse than Cambridge they are 2.1 speakers so I can't compare them to 4.1 or 5.1.

Are these any good comparing to old Cambridge or are these modern ones made of low quality components ?
-Logitech Z506 5.1
-Logitech Z906 5.1
-Creative Inspire T6300 5.1

user33331 wrote:

Back in the early 2000 these speakers where the holy grail. Like best of the best.
Cambridge SoundWorks FPS1600 4.1 FourPointSurround.

- What modern speaker 5.1 set sounds same or better than the old Cambridge ones ?

Please know that I'm certainly not trying to rip on your speakers here.
They were probably considered very good because there were very few 4.1 amplified speaker systems on the market in early 2000s.
For what they are they are probably actually good speakers.
But from a HiFi POV they can't be that good. The small size of the satellite speakers makes it physically impossible for them to faithfully reproduce lower tones. However this is not a problem if you like their sound.
High quality HiFi setups are a botomless money pit anyway because you can always spend more money on better speakers, amplifiers and room optimisation. And once people are done there they're likely to get sucked into the completely unscientific voodoo of "HiFi" audio cables that cost >100$ per meter. 🤣

Without knowing your listening setup (referring mostly to position of speakers relative to hearing position) the best advice for a more faithful audio reproduction is probably to get a decent surround receiver that will take the input provided by your card and connect some passive studio monitors designed to be close to the hearing position and maybe a subwoofer (depending on the monitors they might already produce better bass than your current subwoofer).
But at this point you're in a couple hundered bucks and might realise you don't like the faithful tone reproduction as much as you liked the sound of your original system. Again, wether you like the music reproduction of a speaker set or not is very subjective.
So the most honest advice I can give you is to test some speakers within your price range that provide the functionality you need and look nice and decide which you personally think sound best.
Or stick with the speakers you already know you like. 😁