Compaq AlphaServer DS20 Screams on McAlpin’s STREAM

(c) 1999 by Terry C. Shannon, Shannon Knows Compaq

John D. McAlpin today published STREAM memory bandwith benchmarks for the AlphaServer DS20 at http://www.cs.virginia.edu/stream/standard/Bandwidth.html. The results prove that the soon-to-ship DS20 “Goldrush” server has ‘more memory bandwidth than you can shake a stick at.’ As show in the table and chart below, the DS20 uniprocessor trounces the best single-CPU performance of all rival vendors, and outperforms the Compaq AlphaServer GS140 enterprise server by 55 percent to 90 percent depending on the benchmark.

This is the second set of data indicating that the DS20 will deliver “kick-butt” performance. As discussed in SKC, Compaq reported DS20 SPECint95 and SPECfp95 results indicating that the low-end 500MHz Alpha 21264 DS20 system delivered ~30 percent greater floating-point performance than the 525MHz EV6 GS140 “TurboLaser.”

As we previously pointed out, the DS20 delivered superior floating point performance on the SPEC results because of Fortran compiler optimizations and a low-latency memory system. The DS20’s impressive memory bandwidth is responsible for the system’s Top Dog status in the STREAM benchmarks as well.

SKC anticipates that the 4-processor Compaq AlphaServer ES40 midrange system will offer similarly stellar performance metrics when the system debuts in several months. With the advent of switch-based memory subsystems and faster Alpha 21264 EV6 and EV67 processors, Alpha servers will once again gain a very respectable lead on the competition.

Table 1: McAlpin STREAM Results for Compaq and Rivals

Vendor & System	COPY	SCALE	ADD	TRIAD
Compaq DS20	1077	1244	1179	1323
Compaq GS140	524.7	700	615	817.4
HP C180	262.3	262.3	244.9	242.4
IBM RS6000-591	711.1	695.7	750	800
SGI 2000-2501	332	343	357	358
Sun UE 6001	281	281	224	261