Re: Memory access

From: M. Grove <>
Date: Tue, 13 Jan 1998 16:12:03 -0700

Johan Klockars wrote:
> > Well it's GEMBENCH..... I know that it's not the best to use but it's strange
> > that it should be so expeptinal wrong as it sounds.
> No, that's not strange at all. GEMBench is an incredibly stupid benchmark.
> It's been a long time since I looked at the memory tests, but I seem to
> recall them being made in a way that was very cache unfriendly on an '030,
> but rather nice to the '040 caches.
> I don't know how the '060 caches are organized.
> > the roof.... they were at 2400%. Sounds more correct. Maybe the AB040 fools
> It does?
> A normal Falcon has something like 6Mbyte/s bandwidth to RAM. 24 times
> that would be 144 Mbyte/s, which given a 32 bit bus would require all
> accesses to take less than a single clock cycle at 32MHz.
> Let's say that it was really 128Mbyte/s to keep within the physical limits.
> That still requires an instant setup of each burst transfer, which just
> isn't possible. I'd be very surprised if even 2-1-1-1 was possible.
> An AB040 can reach slightly more than 30MByte/s and I'd say that the
> Hades can at best manage a little more than double that. I'd be surprised
> if it did, though.
> > But also, Petr did say that Quake on the Hades were slower than on the AB040 so
> > something fishy is going on in the Hades.
> An '060 should be _very_ good at Quake.
> I don't think the difference between a Hades040 and an AB040 should be
> significant, though.

There is a bench test call Memspeed. It reflects the speeed you quote
for the A/B,
and also the differences between a standard fast ram card on a TT and my
Aixit card.
It will also document memory speed differences when changing the bus
speed on the
TT and Falcon. I would guess this to be a better test than Gembench. The
Aixit TT
card running at 40Mhz will bench almost the same as the A/B card.
Someone with a Hades
needs to run this for a "correct" FAQ:).

Received on on. jan. 14 1998 - 10:42:00 CET

This archive was generated by hypermail 2.3.0 : ti. nov. 03 2015 - 20:07:53 CET