Date: Mon, 14 Apr 1997 13:15:55 +0100 (BST) From: Stephen Roome <steve@visint.co.uk> To: Tony Overfield <tony@dell.com> Cc: Michael Smith <msmith@atrad.adelaide.edu.au>, David Langford <langfod@dihelix.com>, hackers@freebsd.org Subject: Re: 430TX ? Message-ID: <Pine.BSF.3.91.970414130750.1712J-100000@bagpuss.visint.co.uk> In-Reply-To: <3.0.1.32.19970412103112.006b22b4@bugs.us.dell.com>
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On Sat, 12 Apr 1997, Tony Overfield wrote: > Stephen Roome said: > ] This is interesting, CTCM (motherboard benchmarker program) seems to tell > ] me that I can get almost 56MB/s memory bandwidth. With a 66MHz bus clock > ] I can't see how that this figure can improve much. > > 56MB/s is about half of the "correct" number. Are you sure you're > interpreting the results correctly? For example, if the benchmark is > measuring MOVSD performance, perhaps you're forgetting to double the > numbers, since the operation is a memory copy. If your memory bandwidth > really is only 56MB/s, then that's slow, not fast. Yup it's MOVSD, my mistake, I had a better memory bandwidth checker before which gave figures for each of your Megabytes and gives about 128MB/s on the first MB and obviously less on the others. I expect this is due to the cacheing. > > ] Seeing as Intel seem > ] unlikely to support a 75MHz or 83MHz bus speed then I'd love to know how > ] they intend on doing this. > > I can't speak for Intel, but Intel says this on its www site: > "In addition, the Dual Independent Bus architecture supports the evolution > of today’s 66 MHz system memory bus to a 100 MHz system memory bus within > the next year." I actually meant this in regards of the motherboard, although their chipsets support higher clock speeds (even if not widely broadcasted) their motherboards don't seem to be going anywhere in this area. I wonder how much the motherboard dept. of Intel hate the chipset dept. for saying stuff like this =) (Assuming it's not all contracted out) > Today's typical system has at least 100 MB/s memory bandwidth and many > systems have over 200 MB/s memory bandwidth. Since when did that > become crappy? Well, there are systems out there with GB/s memory bandwidth.. High end ones at that, but if the useable bandwidth is so high then why does the BIOS POST take so long to check the memory ? -- Steve Roome Technical Systems Manager, Vision Interactive Ltd. E: steve@visint.co.uk M: +44 (0) 976 241 342 T: +44 (0) 117 973 0597 F: +44 (0) 117 923 8522
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