Re: SIS 630E perf problems?

[Larry McVoy <lm@bitmover.com>]

> I've used a few funky SIS chipsets, on and off, for a long time now, and they 
> always have one leeeetle problem...
> 
> Try benchmarking it with a lower screen resolution (like 640x480x256 colors). 
>  If the video is sharing main memory, it's sharing the memory bandwidth as 
> well.  So you've basically got a constant ultra-high-priority DMA going to 
> the screen, sucking up bandwidth and fighting with everything else.  
> (Everything else MUST lose or the display would sparkle.  
> 1280x1024x32bitsx70hz is HOW much bandwidth we're talking here?)

OK, a copuple of updates on this:

I wasn't running X when I ran the benchmarks.

I played around with the bios settings enough to make the machine not
pass POST anymore so I reset the CMOS.  Doing that, plus telling the
system to autodetect DRAM clocks dropped the latencies down to 260ns
outside of X and 281ns with X running.  Still not fantastic but good
enough I suppose.

In reference to the fans that someone else mentioned: I think it is the
CPU fan making the noise.  Regardless, the MTBF of the power supply fans
is one year.  I have about a dozen of generation 1 of these bookpcs and
the fans all started failing at 1 year and frying the power supplies.
Those dinky power supplies are hard to find so you want to avoid this.
We bought a pile of fans and replaced them all; one benefit is that the
higher quality fans are much less noisy.  Something to look into.
-- 
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Larry McVoy            	 lm at bitmover.com           http://www.bitmover.com/lm