Roland duo-capture - will it improve my Sonar X3e performance?

Please, bear with me for a few minutes. I have and Asus P5Q-E motherboard with onboard audio chip which cannot be used for DAW purposes, no matter which driver and mode one uses. I've tried WASAPI and ASIO4ALL, nothing works satisfactorily. So I have Creative Audigy 2 ZS which has it's own ASIO drivers and that's what I work with now. It works fine as long as I don't work with many tracks simultaneously and as long as I don't use VST effects. If I do use many VST tracks and some effects, audio shutters and chokes and finaly forces me to restart the session.
I don't need audio inputs;  I work only with VST instruments. So I wonder, would Roland's Duo-capture be the right thing for me? I need fast and stable ASIO driven interface, so I can burden my Sonar session with many VST tracks and not too many effects. My computer isn't underspeced, CPU, RAM and HDD metters don't peak and I have plenty of power left when audio drops down, probably because Audigy 2 ZS isn't good enough for DAW.
So - does anyone know if Duo-capture realy has low-latency ASIO driver as advertised on Roland web page? Would I be wrong if I assume that Duo-capture has the same ASIO driver as it's bigger brothers like Tri-capture or Quad-capture? Those interfaces are very expensive to me and, sincerely, I don't need features they offer. I don't need inputs, preamps, direct monitoring etc. Or, since it's much cheaper than bigger ones, does Duo-capture has some mediocre ASIO driver which wouldn't be much of an improvement to my current ASIO driver provided by Audigy 2 ZS?
I've tried all possible combinations of drivers and ASIO4ALL and WASAPI configurations available on my present configuration and Audigy 2 ZS's ASIO driver works better than any of those, but even loosing the latencies to slow settings doesn't help big projects and audio freeze downs are very frequent.
I'm in no way biased toward Duo-capture. If anyone can recommend audio interface without many bells and whistles, but with excellent ASIO driver, please do so. Keep in mind my budget is 150 dollars max.
Thanks in advance.
Best regards,
Ivan

Erm...I left out a small detail. I use A800pro for actually playing and recording vst instruments, so I do need low latency. I'm not after a benchmarking, but I want to be able to play and record many tracks in one session without noticable lag and without audio issues.

You've been of great help and I'm thankfull, but would you suggest Duo-capture would perform equally well ASIO-wise as Duo-capture EX, which You've provided review for? Duo-capture EX costs 250 dollars and Duo-capture costs 100 dollars (prices in Croatia).

Thank You very much. This is exactly an answer I was hoping for. As for the rest of the system, no worries there.
Best regards.

Wow that is one of the worst guides I've ever seen for "optimizing" your computer. It could lead to a score of problems and it doesn't even really tell what setting it's changing and what that means for most of them.

I switched from Asio to wdm drivers on my octa due to an issue I had with multiple instances Kontakt and I actually get a much lower latency and very stable performance. My friend achieved the same results with his quad, so regardess of what drivers you use, it provides excellent latencyaas Asio works perfectly well enoughiin 99% of situations.

Bibs