[Sunhelp] Sol8 on SS5-110

[Kevin Stevens]

> On Thu, 1 Jun 2000, Christopher J Ceska wrote:
>
> > bottom line, the SX is faster than any SBUS buffer at any
> > resolution/color depth.  There is documentation from sun and third
> > parties that back this up.  SBUS == slow.
>
> The SX is not faster in 24bpp mode than a cg6 is in 8bpp mode.  Xstone
> results and empirical testing of my dual-headed SX/TGX bear this out.
>
> The theoretical maximum bandwidth to the SX is 4x greater than that to a
> (32-bit) sbus based framebuffer, but SX has to move 4x as much data in
> 24bpp mode. Add to this the fact that more data must be pumped in from
> main RAM and it is likely to be rougher on the caches and you have an
> overall slowdown. The SX is also impacted negatively by mbus latancy since
> it is noncacheable, this can be seen by comparing raw bitblitting
> performance of a SS20/50 and a SS20/61 (the 50 will win).
>
> That said, the SX is definately the fastest 24bpp framebuffer for
> pre-Ultras.  Comparing it against 8bpp cg6 cards isn't really fair.

This makes sense, and was actually my line of thinking when my SX appeared so
slow compared to a cg6 machine.  However, I don't really have a fervent
requirement for 24bit color, and would prefer the speed.  I've found options for
changing resolution, etc. on the SX, but can't find one for changing the color
depth (maybe it's in the X11 or CDE configuration??).  Is it possible to change
the SX into 16 or 8 bit depth, and would doing so gain a significant speed
improvement?

KeS