PA-RISC Performance

The main competition of PA-RISC during the 1990s were other Unix platforms on RISC architectures: Sun SPARC (Solaris), Digital Alpha (Tru64 and OSF), SGI with MIPS (Irix), and IBM POWER (AIX and others). In the late 1990s, Intel Pentium and P6-based sucessors also became serious competitors (Windows and Linux).

PA-RISC CPU History Periods
Period Processors Competition
PA‑RISC 1.0
1980s		 TS-1, NS-1, NS-2, PCX Early RISC and CISC R2000, R3000, SPARC, i386, i486, VAX, 68040
PA-RISC 1.1
1990s		 PA-7000, PA-7100, PA-7200,
PA-7100LC, PA-7300LC		 Early RISC and CISC
RISC and IA32		 R3000, R4000, 88000, POWER, SuperSPARC, PPC 604, Alpha 21064, 21164, Pentium and Pro
PA‑RISC 2.0
1990s-2000s		 PA-8000, PA-8200, PA-8500, PA‑8600, PA-8700, PA-8800, PA‑8900 RISC and IA32
Supercomputers		 R10000, R12000, Pentium II, Xeon, UltraSPARC, Alpha 21164A, 21264, 21364, POWER3 and 4
HP IA64
2000s		 Merced, Itanium 2 RISC and IA32
Supercomputers		 PA-RISC, Alpha 21364, Pentium III and 4, Athlon and Opteron

While PA-RISC processors were usually faster than their competition at the same clock speed, they were expensive to fabricate. Their platform, HP 9000 on PA-RISC and HP-UX, was usually exclusively priced and was often used for specialized technical workloads that made use of their strengths in floating point and numerical processing,

Companies such as HP and IBM could justify developing very-high-end processor designs, even though the unit volume will be small, because the profits per system are far higher than the profits per microprocessor chip, as MPR put it in 1992.

So, how did PA-RISC fare in benchmark scores of the SPEC suite?

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PA-RISC vs. early RISC and CISC

In the RISC infancy in the late-1980s, PA-RISC was in the 32-bit RISC processors performance midfield. HP PA-RISC got stronger in the early to mid-1990s with higher SPEC scores than competing early RISC designs and improved CISC processors.

Typical PA-RISC SPEC92 and SPEC89 scores
* - approximate
Processor Clock Year SPEC89 SPEC92
int  fp
NS-1 30 MHz 1987 9.5
PRISM 18 MHz 1988 19
PA-7000 50 MHz 1991 49 31 47
PA-7100 75 MHz 1992 107* 82 127
PA-7150 125 MHz 1992 182* 136 201
PA-7100LC 100 MHz 1994 117 144
PA-7200 120 MHz 1995 167 269
PA-7300LC 180 MHz 1996 200* 275*
Based on old SPEC92 archives
* - unsure/unlikely
Processor Clock Year SPEC89 SPEC92
int  fp
MIPS R2000 16MHz 1986 11.8 8.4
DEC KA46 VAX 22MHz 1991 12 11.1 12.6
Motorola 68040 25MHz 1990 10.3 12.2 9.3
MIPS R3000 33MHz 1988 25 20.9 23.4
Motorola 88100 33MHz 1988 18 27.7 18.8
Intel 486DX2 66MHz 1992 25 35.8 16.1
IBM POWER 41MHz 1990 75 40.7 83.3
MIPS R4000 50MHz 1991 36 43.2 42.1
DEC KA49-C NVAX 100MHz 1995 45
Sun SuperSPARC 40MHz 1992 71 50.2 60.2
Intel Pentium 60MHz 1993 60.6 55.1
DEC Alpha 21064 100MHz 1992 59* 74.6 95.2
MIPS R4400 100MHz 1993 73 85.9 93.6
Intel Pentium 100MHz 1995 118.1 89.9
PowerPC 604 133MHz 1995 156.8 144.8
DEC Alpha 21064 200MHz 1994 184 135.8 160.5
DEC Alpha 21064A 266MHz 1993 198.6 262.5
Intel Pentium Pro 150MHz 1996 276.3 220.2

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PA-RISC vs. RISC and IA32

PA-RISC was a fast architecture compared to other RISCs in raw CPU power throughout the 1990s. When others like Alpha and Intel P6 increased frequencies in the late 1990s, PA-RISC soldiered on with lower clock but still high SPEC scores.

Typical SPEC scores of HP PA-RISC computers
Processor Clock Year SPEC95
int  fp		 SPEC2000
int  fp
PA-7000 50 MHz 1991 1.20 2.00
PA-7100 75 MHz 1992 1.53 2.46
PA-7150 125 MHz 1992 3.97 4.61
PA-7100LC 100 MHz 1994 3.76 4.06
PA-7200 120 MHz 1995 6.06 8.14
PA-7300LC 180 MHz 1996 9.22 9.43 87 60
PA-8000 180 MHz 1996 11.80 18.70
PA-8200 200 MHz 1997 14.20 21.40
PA-8500 440 MHz 1998 31.80 52.40 313 321
PA-8600 552 MHz 2000 42.10 64.00 432 433
PA-8700 750 MHz 2001 57.60 85.90 604 576
PA-8800 1 GHz 2004 1001
PA-8900 1.1 GHz 2005
SPEC95 and SPEC2000 scores of other RISC and CISC
Processor Clock Year SPEC95
int  fp		 SPEC2000
int  fp
Sun SuperSPARC 40 MHz 1992 1.13 1.38
DEC Alpha 21064 100 MHz 1992 1.48 2.79
Sun SuperSPARC II 75 MHz 1994 3.11 3.10
IBM PowerPC 604 100 MHz 1992 3.59 3.20
MIPS R5000 150 MHz 1996 3.97 4.20
DEC Alpha 21064A 266 MHz 1993 4.18 6.27
Intel Pentium 100 MHz 1994 4.04 2.35
Intel Pentium Pro 166 MHz 1995 7.11 6.21
DEC Alpha 21164 300 MHz 1998 7.33 12.20 161 158
IBM PowerPC 604e 166 MHz 1996 7.52 8.52
MIPS R10000 196 MHz 1996 10.1 8.7
Intel Pentium II 333 MHz 1997 13.0 9.4
Sun UltraSPARC IIi 333 MHz 1997 14.1 18.3 133 126
Intel Pentium III 500 MHz 1999 20.7 14.7 231 191
MIPS R12000 400 MHz 1998 24.2 43.5? 320 319
DEC Alpha 21264 500 MHz 1998 27.3 57.7 311 382
MIPS R14000 600 MHz 2001 483 499
Sun UltraSPARC III 1 GHz 2001 511 688
IBM POWER4+ 1 GHz 2003 617 862
DEC Alpha 21364 1 GHz 2001 689 975
AMD Athlon XP 2.2 GHz 2002 1080 873
Intel Xeon 2.8 GHz 2003 1249 1081
AMD Opteron 250 2.5 GHz 2004 1619 1652
Typical SPEC scores of HP Itanium computers
Processor Clock Year S’95 SPEC2000
int  fp
Itanium Merced 800 MHz 2001 365 610
Itanium McKinley 1.0 GHz 2002 807 1422
Itanium Madison 1.5 GHz 2003 1315 2106

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PA-RISC vs. Supercomputers

PA-RISC started its life as conservative RISC design for Unix computing in the 1980s. Performance in the early years was on par with other RISC and Unix platforms, but in the 90s, PA-RISC grew into a fast technical RISC platform with 64-bit PA-8000 CPUs.

But supercomputers?

HP used PA-RISC’s floating-point prowess and the newly-acquired Convex Exemplar technology to compete with massively-parallel and vector supercomputers from Cray and its RISC competitors. HP PA-RISC was often faster than other parallel RISC platforms but still slower than vector computers, in Linpack MFLOPS.

Notably, a HP 9000 735/125 workstation from 1991 was as fast as a Cray-1S supercomputer from 1979, while a HP 9000 K460 from 1996 was faster than a Cray Y-MP EL from 1992. At the top end in the late-1990s, Cray T90 and SV1 vector computers were still much faster than comparable HP V-Class offerings based on Convex Exemplar and 64-bit PA-RISC.

And the 1980s Cray computers were seriously fast.

PA-RISC Linpack MFLOPS (TPP) and HPLinpack GFLOPS (Rmax)
Computer Processor Year Linpack
TPP  Rmax
HP SuperDome 64 PA-8700 750 MHz
16 PA-8700 750 MHz		 2001
17660		 133.2
HP SuperDome 32 PA-8500 552 MHz
16 PA-8500 552 MHz		 2000
12200		 47.01
HP 9000 V2600 32 PA-8500 552 MHz
16 PA-8500 552 MHz		 1999
1999
9068		 36.01
20.45
HP 9000 V2500 32 PA-8500 440 MHz
16 PA-8500 440 MHz		 1998
1998
8217		 31.59
17.47
HP 9000 N4000 8 PA-8600 550 MHz 1999 7762 12.37
HP 9000 V2250 16 PA-8200 240 MHz 1998 5935 10.65
HP 9000 V2200 16 PA-8200 200 MHz 1997 4832 9.20
HP X-Class
Convex SPP2000		 64 PA-8000 180 MHz
16 PA-8000 180 MHz		 1997
1997
4609		 27.56
7.78
Convex SPP1600 32 PA-7200 120 MHz
8 PA-7200 120 MHz		 1996
1996
934		 5.45
1.45
Convex SPP1000 64 PA-7100 100 MHz
8 PA-7100 100 MHz		 1994
1994
751		 6.19
1.01
HP Visualize C240 1 PA-8200 236 MHz 1997 667
Convex SPP1200 32 PA-7200 120 MHz
8 PA-7200 120 MHz		 1996
1996
656		 3.96
1.02
HP 9000 K460 1 PA-8000 180 MHz 1996 510
HP 9000 735/125 1 PA-7150 125 MHz 1992 120
HP 9000 750 1 PA-7000 66 MHz 1991 49
Linpack MFLOPS (TPP) and HPLinpack GFLOPS (Rmax) archives
System Processor Year Linpack
TPP  Rmax
Cray T90 T932 32 Cray ECL 450 MHz 1995 29360 61.80
Cray SV1 24 Cray CMOS 300 MHz 1998 10420 38.31
AlphaServer 8400 32 Alpha 21164 625 MHz
16 Alpha 21164 625 MHz
8 Alpha 21164 625 MHz		 1998
1998
1998

3608		 17.96
9.59
SGI Origin 2000 32 R12000 300 MHz
16 R12000 300 MHz		 1998
1998
3970		 15.77
8.71
Sun Starfire 28 Sun UltraSPARC-II 333
32 Sun UltraSPARC-II 300		 1997
1997
5187		 15.66
AlphaServer ES40 4 Alpha 21264 667 MHz 2000 3804 4.11
IBM RS/6000 SP 4 POWER3 375 MHz 2000 3700 4.64
Sun Enterprise 6k 16 Sun UltraSPARC 250 1996 3493 7.21
Cray-2/4-256 4 Cray ECL 243 MHz 1985 1226
Cray Y-MP M98 4 Cray ECL 166 MHz 1992 1114
Cray C90 1 Cray 238 MHz 1991 902 2.92
Cray X-MP/416 4 Cray ECL 117 MHz 1986 822
Intel DELTA 512 Intel i860 MHz 1991 446 13.9
Cray Y-MP EL 4 Cray CMOS 33 MHz 1992 345
nCUBE 2 512 nCUBE 20 MHz 1989 204 0.95
CDC CYBER 205 4-pipe ECL 1981 195
Cray X-MP 1 Cray ECL 100 MHz 1982 184
Cray-1S 1 Cray ECL 80 MHz 1979 110
CDC 7600 1 CDC 36 MHz 1969 10
CDC 6600 1 CDC 10 MHz 1964 4

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Documentation

Most of the SPEC scores are from official SPEC results websites, now archived. Some scores are from vendor product pages, now also archived or lost.

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