Computex 2001 - Day 2

i845 (Brookdale) DDR

Nearly every motherboard manufacturer we talked to had two i845 motherboards at the show: a PC133 i845 on display, and a DDR i845 underneath the table that Intel wouldn’t allow them to show. 

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In our Day 1 coverage we explained why Intel isn’t allowed to promote the DDR i845 platform until January 1, 2002 at the earliest.  But that doesn’t mean that motherboard manufacturers don’t have motherboards ready to go if need be.

Another thing we were able to do is spend some time benchmarking an i845 with regular PC133 SDRAM.  The performance tests we were able to run were limited to one or two benchmarks, but the results we saw were pretty interesting. 

In our most recent AMD 760MP and Athlon MP Review we provided a good amount of memory bandwidth figures produced by SiSoft Sandra 2001’s memory benchmark. 

The important thing here isn’t to look at the standings, but the percent utilization of the memory bus.  For example, in the FP STREAM test, the Pentium 4 1.5GHz offers 1400MB/s of memory bandwidth yet the chipset can deliver a theoretical maximum of 3.2GB/s of memory bandwidth (~3200MB/s).  This indicates that around 44% of the memory bandwidth is being utilized. 

In the case of the single processor Athlon MP, only 36% of its DDR266 memory bandwidth is being utilized.  You can already see that the Pentium 4’s FSB is able to take advantage of higher bandwidth memory technologies much more effectively than the Athlon’s FSB (400MHz data clock vs 266MHz data clock). 

The Pentium 4 1.5GHz on a PC133 i845 platform manages to use over 61% of its peak theoretical memory bandwidth.  While in the first two cases memory bandwidth wasn’t the limiting performance factor, in the case of the i845 the Pentium 4 comes very close to saturating the PC133 memory bus.