On Dec 4, 11:58am, Bill Broadley wrote:
>The motherboard post mentions 84MB/sec read, 104 MB/sec write bandwidth I
>assume this is for the 50 Mhz motherboard?
>So if we go with the 4200 we would be at 40 Mhz or 67.2/83.2 Mb/sec??
>Or would the bandwidth stay the same?
>SGI claimes 267 Mb/sec but a similiar memory interface may not be cost
>effective (let alone designing it.)
>I wrote a memory benchmark program (membench at neurocog.lrdc.pitt.edu
>~ftp/pub) and was wondering what it would report on a SGI mips 4000 system.
>Any takers out there?
>Alpha 133 Mhz gets 80 Mb/sec
>Hp 735 99 Mhz gets 85 Mb/sec
>486dx2 66 Mhz gets 16 Mb/sec
>So obviously 67/83 would be very competitive. I'm still very curious
>if the SGI's would score 267 though.
On an SGI Indy mips 4000PC 50/100MHz with 8K/8K L1 cache (no L2) I get
36 or 43 MB/sec (not sure to interpret this) if I've done this right.
Bill, I did (slightly edited)
./membench 128 2000
Time Stride reads per % speed MB per
per loop (ints) second (in K) improvement sec
8.60 4 1860.5 21.0 29.1
6.88 5 1860.5 0.0 36.3
5.73 6 1861.5 -0.1 43.6
Hmm, I start to believe that the correct number is 29.1 MB/sec. Whatever
size I use (as long as it's more than 8 (KB)) I get ~29 MB/sec with a
stride of 4 (i.e. 32 bytes). After that the speed improvement drops to