Benchmarking
In many cases, the battle falls to who has the most muscle. Creative cites 1000 MIPS for the 10K1. Aureal is quick to say 600-800 "hardware" MIPS for the Vortex 2, which translates into roughly 1200-1600 "DSP" MIPS for comparison to the SB Live. While we have yet to see any game or program that will truly tax the limits of either processor, we can test the streaming capabilities of each card. Keep in mind that the drivers for the MX300 are still in beta, and in fact Diamond has delayed the MX300 slightly (until Thanksgiving or so) to stabilize the drivers. For this case, test results won't count for or against each card considering the unfinished status of the Diamond drivers, but they will show any drastic differences in performance.
In a related note, Creative has had a number of problems with the Sound Blaster Live! drivers for Windows NT. I used to run NT regularly when I first got my SB Live, everything seemed OK. Then I started playing music and games off my system again (there's only so much NT can do to keep you away) and my system crashed within minutes each and every time I started playing an MP3 or any game for an extended period of time. Brilliant genius that I was, I assumed Winamp had a bug streaming files over the network, or that Quake II was crashing due to an overheated (and overclocked) Voodoo2. I eventually switched to Win98 and the problems disappeared. Later on, I found out at Zanshin's GL Dojo that the problems were due to the Live card and its horrendous NT drivers. UGH. To think I formatted both my hard drives, gave up RAID, and moved to a "toy OS" all because of this. Due to increasing pressure (and I'm going to assume a desire simply to do the Right Thing), Creative is working on the problem, and you can find the latest NT (and 95/98) drivers at Sblive.com. The good news is that the Win98 drivers appear completely ROCK SOLID, and I've never had a problem with them, despite hours of continuous tinkering (the price of reviewing hardware) with and without reboots.
OK, enough rants. Running on identical machines, I first started by running a standard Quake II timedemo. Over three consecutive Timedemos with nothing in the background, the SBLive clocked in an average of 102.5 fps. The MX300 stayed a rock-solid 100.7 for all three tests. Timedemo2 showed nearly the same result, with the SBLive at 102.4 and the MX300 at 100.1. Unreal Timedemo yielded the similar results, with both cards clocking in between 45 and 47 fps through three passes of the intro flyby.