Doing things we ought not to do
Naturally, some of the Tiger MPX's spec-sheet restrictions looked like challenges to us. So we tried a bunch of messed up configurations to see if they would really work. Among them:

• Running a pair of 1GHz Durons — Running Durons in SMP is an attractive alternative to building a single-processor system based on a more expensive Athlon XP, so there's some real interest in this one. Like the Tiger MP before it, the Tiger MPX had no trouble at all running a pair of "Morgan" Durons (the kind derived from the Athlon MP's Palomino core) in a dually config. In fact, we've got a full set of benchmarks with dually Durons.

• Running an Athlon MP 1800+ and an Athlon XP 1800+ — Again, no problems here. If you want to save a buck, you might be able to get away with running a pair of Athlon XPs on a Tiger MPX. Heck, other than the markings on the CPU cores and the fact the MP's L1 bridges are not severed, the Athlon MP and XP look identical. They've just gotta be the same chip.

• Running a Duron 1GHz and a Duron 1.1GHz — We put a Duron 1.1GHz chip into the CPU 1 socket and a Duron 1GHz into the second socket. The system booted into Windows and ran stable. Both WCPUID and SiSoft Sandra reported that both processors were running at 1.1GHz. Apparently, the system picked up the multiplier from CPU 1 and enforced it for CPU 2, as well.

• Running a pair of Durons on a 266MHz bus — We tried this one inadvertently the first time we installed the Durons into the board. Unfortunately, our Durons weren't up to the task. The system refused to POST.

• Running a full load of unbuffered DIMMs — So if you slap four DIMMs full of high-quality DDR memory into the Tiger MPX's DIMM slots, what happens? We put in a gig's worth of Crucial and Kingmax (all based on Micron chips) and gave it a go. We were able to get the system to boot and run a solid mix of Windows apps, like so:
  

  
  The money shot. Click for the full-size picture.

  However, after a little while, the system locked up. We cut down to three DIMMs, but the results were the same. On the other hand, the system was stable with a pair of unbuffered DIMMs or with registered ECC memory. That's disappointing, because we were so close to being able to get away with unbuffered memory modules. But there's a reason Tyan's specs call for registered DIMMs.