ned Productions – Niall’s Tyan Tiger MP resources

Background

I bought all quality components, from the case down its PSU. Here's a quick list of the important stuff:

• Two AMD Athlon XP 1700's
• Two ThermalRight SK6 heatsinks with 27cfm YS Tech fans
• 4x 256Mb Crucial memory (the ones which require entire body weight to insert properly)
• 431W Enermax PSU (the beefier one, there are two 431W variants)
• Secondary case exhaust

I built it with a mind to balancing cooling with noise, hence the YS Tech fans (27cfm) instead of the more common Delta fans (40cfm). It all works swimmingly during the winter when average CPU temperature is 65C (fully loaded) and the room is around 20C. Unfortunately, as summer here in Spain began to arrive, the machine kept crashing. I installed this very handy CPU temperature monitoring utility which is much less annoying than Tyan's System Monitor and noticed the crashes began when the CPU temperature (either) exceeded 72C.

As the temperatures kept going up (say 27C ambient), I could no longer do the video processing I do a lot of. Hence I had to underclock the machine, switching down to 100Mhz FSB instead of 133Mhz, thus making my 1700's (1533Mhz) behave like 1150Mhz (but a max of 68C with 27C ambient).

This was all well and good, if annoyingly slow. However, I noticed that VirtualDub kept hanging on frame 9995 when converting MPEG1 to DivX. I tried everything, even a fresh install and old versions of VirtualDub, but nothing worked. I tracked it down to the MP3 encoding side, tried a dozen different codecs but still same problem. The identical conversion worked perfectly in other applications. Returning the FSB to 133Mhz solved the problem, except for the random crashes.

With temperatures set to hit 40-45C in August, it was clear even a better cooling solution would not help for long. Something else was needed.

Solution

I thought that given the four FSB jumpers on the S2460 J52, J53, J48, J49 there must be some intermediate solution. So I unplugged the hard drives and began trial and error, and interestingly there is one other setting which works without crashes:

These settings apply to the v1.03 revision of the Tyan Tiger MP board. I didn't find any other settings which would boot, although I didn't experiment much with J48 and J49 because I had to keep taking out a PCI card each time.

This setting is about 12% faster than 200Mhz, but 16% slower than full speed. Definitely better than being technically 25% slower though (more about this below). More importantly, the frame 9995 problem doesn't appear at this speed.

Needless to say, this is an unofficial setting which will void your warranty (as will using anything other than an AMD Athlon MP BTW). It may work on the Thunder, v1.00 revision of the Tiger MP (except reversed like they are on that board) or the Tiger MPX but I don't know because I don't have access to those boards. Finally, using the 224Mhz setting may cause your PCI bus (and hence AGP but twice so) to run at 37Mhz which could damage some cards - most quality cards, like in Socket 7 days, will run fine at this speed.

Results

I do lots of MPEG1=>DivX with VirtualDub, so that's what I'm basing my results on (it's especially good because it makes good use of two processors). This is how long to convert a 43 minute MPEG1 VCD to DivX (Fast Recompress), with the FSB speed first and the processor speed after (real speed, not AMD's naming system):

* The 200Mhz is VirtualDub's estimate just before frame 9995

Is it really possible 200Mhz operation is over twice as slow as the 266Mhz operation? Well even subjectively speaking, it certainly feels like it - the machine feels only maybe thrice as fast as my old 400Mhz AMD K6-3 (although it needs 3.5 hours to do the above job!) whereas 266Mhz operation feels like 10x times and more. I did notice however that with 200Mhz, average processor use is around 56%. With 224Mhz 85% and with 266Mhz 98%.

With this evidence in addition to the frame 9995 problem, which from my searches on the internet would indicate I am the only person ever to experience this, my opinion is that 200Mhz operation is broken on this motherboard. I haven't found any benchmarks regarding 200Mhz operation with this board, so I can't say if it's just my config or everyone's. One thought of mine is that maybe the cache coherence bus between the processors is somehow degraded thus causing a lot more fetches to main memory and hence downgrading the effectiveness of having more than one processor, but that would surely increase processor usage?

Conclusions

I suggest this cause of the cache coherency bus being impaired because other applications will take the 200Mhz config to 100% usage, but of course VirtualDub is special in that you have both processors working together on exactly the same data at the same time which really tests the cache coherency hardware.

One last note: For any of you who are smokers, you'll know already that modern heatsink and fans are extremely sensitive to dust accumulation. Cleaning your heat sink and fans every month can drop your processor temperature by 4C, so it's well worth it.

I hope this page has been of use to some of you. We adopters of new technology always have to put up with some idiosyncrasies (certainly the getting the Crucial memory into those slots welds your fingers, but it does work eventually) but I have to say, when this board runs, it runs as fast as any computer I have ever used (better than a dual 2.2Ghz Xeon too might I add!).

Whatever you use your computer for, may you have fun and many years of dedicated service!