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 Performance Periods
Competition PA-RISC
Early RISC, CISC R2000, R3000, R4000, 88000, SPARC, i386, i486, VAX, 68040 TS-1, NS-1, NS-2, PCX
PA-7000, PA-7100		 Infancy (1.0)
Growth (1.1)
RISC and IA32 R5000, R10000, R12000, SuperSPARC, PowerPC, Alpha 21064, 21164, Pentium, Pentium Pro, Pentium II PA‑7200, PA‑7100LC, PA‑7300LC
PA-8000, PA-8200, PA-8500		 Maturity (1.1, 2.0)
2000s, Itanium R10000, R12000, Pentium II/III, Xeon, UltraSPARC, Alpha 21264, 21364, POWER3 and 4, Opteron PA‑8600, PA-8700, PA-8800,
PA‑8900, Merced, Itanium 2		 Decline (2.0, EPIC)
Supercomputers Cray, Alpha 21164, 21264, POWER3 PA‑7200, PA‑7100LC, PA‑7300LC
PA-8000, PA-8200, PA-8500		 Maturity (1.1, 2.0)

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.

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Early RISC and CISC

Period Years PA-RISC Competition
Infancy
PA-RISC 1.0		 1986—1990 TS-1, NS-1, NS-2, PCX R2000, R3000, SPARC, i386, i486, VAX, 68040
Growth
PA-RISC 1.1		 1991—1993 PA-7000, PA-7100 R3000, R4000, 88000, POWER, SuperSPARC,
PPC 604, Alpha 21064, 21164, Pentium and Pro

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.

HP TS-1 competed against other early RISC offerings like R2000 and early Sun SPARC, but mostly against established CISC offerings like VAX and Motorola 68000. It was not a very fast processor implementation.

HP NS-1 and NS-2 PA-RISC processors competed with other early RISC platforms like MIPS R2000 and R3000 as well as early SPARC and also Apollo PRISM and Motorola 68030/68040. PA-RISC had roughly similar to slighly lower performance than them.

HP PCX was a rather fast early RISC design, roughly on par with later SuperSPARC and early IBM POWER RISC platforms and still faster than contemporary Intel CISC offerings like 486DX and early Pentium.

HP PA-7000 PA-RISC processors (1991) were average RISC performers of the early 1990s with roughly the same performance as MIPS R3000A (1992), Motorola 88100 (1988) and SPARC (1991 implementations) but slightly slower than IBM POWER1 (1990), Sun SuperSPARC (1992) and MIPS R4000 (1991) at similar clocks.

Compared to personal computers in that era, PA-7000 were faster than Intel 486DX2 (1992) and level with later Pentium P5 (1993) at the same frequencies, but significantly stronger in floating point than both.

HP PA-7100 PA-RISC processors were rather fast microprocessors for their time in 1992, used in many HP 9000 workstations and servers. They were on par with their RISC competition and beating even newer processors in floating point. At the same clock, PA-7100 were almost level with Pentium P54C (1994) and MIPS R4400SC (1992) but significantly faster in floating point, SPEC95.

They were significantly faster than DEC Alpha 21064 (1992), slightly faster than IBM PowerPC 604 (1994) but beaten by higher-clocked Intel Pentium Pro (1995).

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
Intel i860 40MHz 24.1
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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RISC and IA32

Period Years PA-RISC Competition
Growth
PA-RISC 1.1		 1991—1993 PA-7000, PA-7100 R3000, R4000, 88000, POWER,
SuperSPARC, Alpha 21064, Pentium
Maturity
PA-RISC 1.1		 1994—1999 PA-7200, PA-7100LC, PA-7300LC
PA-8000, PA-8200, PA-8500		 R10000, R12000, Pentium Pro, Pentium II,
UltraSPARC, Alpha 21164A, 21264, 21364

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.

PA-7100LC were fast, integrated low-cost microprocessors, on par with RISC and PC architectures of the time. At the same clock, PA-7100LC were in the ballpark of IBM PowerPC 604 (1994) and beat Pentium P54C (1994) and MIPS R4400SC (1992) in SPEC92 scores. They were much stronger in floating point.

As MPR put it, PA-7100LC were significantly faster than the PowerPC 601 and dramatically faster than the TI microSPARC, and had far better FP performance than Sun’s microSPARC II and outran the fastest SuperSPARC chip in SPEC92 scores.

HP PA-7200 PA-RISC were very strong microprocessors for 1995, usually above their RISC competition in technical computing. PA-7200 were much faster than IBM PowerPC 604 (1994), Pentium P54C (1994) and MIPS R5000 (1996) at similar frequencies with almost twice the performance in floating point.

PA-7200 were almost equal to higher-clocker Pentium Pro (1995) and UltraSPARC (1995) and not far from Digital Alpha 21164 (1996) at significantly higher clock.

PA-7300LC PA-RISC were solid low-cost RISC processors, on par with competing microarchitectures in 1996. At the same clock, PA-7300LC were slightly faster than Sun UltraSPARC (1995), Pentium Pro (1995) and PowerPC 604e (1996), in SPEC95 scores. Floating point results were weaker.

Even though HP designers planned the PA-7300LC to out-perform every processor shipping today [1995] except Digital’s 21164, it was clear high-end RISC chips from a number of vendors are likely to surpass the 7300LC’s performance before it debuts. HP had a lack of processor design resources and its competitive edge has ebbed after new processor introductions.

In comparison, MIPS R10000 (1996) and Pentium II (1997) processors beat PA-7300LC with higher clock rates. The 64-bit PA-8000 follow-on PA-RISC processors from HP were about 30% faster at the same clock.

PA-8000 performance
PA-8000 performance, © HP 1996

PA-RISC 2.0 PA-8000 were very fast 64-bit microprocessors in 1996, above the RISC competition for technical computing. They were faster than IBM PowerPC 604e (1996), Pentium Pro (1995), Pentium II (1997) and MIPS R10000 (1996) at similar clocks, and much stronger in floating point.

PA-8000 were almost par with Pentium II (1997) and UltraSPARC IIi (1997) sold at significantly higher clocks. They were more than ⅓ faster at the same clock than the 32-bit PA-7200 and PA-7300LC predecessors.

PA-8200 Performance
RISC Performance in ’97 © MPR Conference

HP PA-8200 PA-RISC were again very fast 64-bit microprocessors in 1997, and above much of the RISC competition in technical computing. They were significantly faster than Pentium II (1997), UltraSPARC IIi (1997) and Digital Alpha 21164A (1996) that had twice the clockspeed.

Newer MIPS R10000 CPUs (1996/1997) with large caches were only slightly slower than PA-8200. PA-8200 in turn were a bit faster than the core 64-bit PA-8000, released a year earlier (1996) at lower frequencies.

HP PA-8500 PA-RISC were some of the fastest 64-bit microprocessors in 1998. They were significantly faster than Pentium II (1997), Pentium III (1999) and Digital Alpha 21264 (1998) at the same or higher clock speed. IBM POWER3 (1998) and UltraSPARC IIi (1997) were almost on par at the same clock. SGI MIPS R12000 (1998) was slower than PA-8500 and only sold at lower frequencies.

PA-8500 were shipped with higher clock speeds than earlier 64-bit PA-8200 (1997) and slightly faster in integer and significantly faster in floating point. Notably, PA-8500 won the Microprocessor Report’s Best RISC Processor in 1999, when it is destined for the scrap heap due to Itanium arrival.

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
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

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2000s and Itanium

Period Years Processors Competition
Decline
PA-RISC 2.0		 2000—2005 PA-8600, PA-8700, PA-8800,
PA-8900		 R12000, Pentium III, Xeon, UltraSPARC III,
Alpha 21264, 21364, POWER4
Decline
EPIC VLIW		 2001—2006 Merced, Itanium 2 PA-RISC, Alpha 21364, Pentium 4, Opteron

HP produced still fast processors during the years of its Decline in the early-2000s, before and during the Itanium transition. Since HP lacked adequate fabrication facilities for high-performance CPUs, the last PA-RISC processors were fabbed at Intel and later IBM with very advanced processes, resulting in rather fast CPUs.

Even though a bit clock-speed limited, 64-bit PA-RISC processors were still very performant CPUs of the early 2000s compared to other RISC architectures and even the competition of 64-bit Intel/AMD and in-house Itanium (EPIC).

HP PA-8600 PA-RISC were fast 64-bit microprocessors of the early millenium (2000) and followed the PA-8500 performance-wise with improved frequencies. The PA-8600 were in the same ballpark as higher clocked UltraSPARC III (2001), Pentium III Xeon (1999) and faster than (slightly outdated) Digital Alpha 21264 (1998).

Performance was even with IBM RS64-VI (2000) and MIPS R14000 (2001) RISC processors at similar clock, while the newer Digital Alpha 21364 (2001) was faster at higher frequencies. PA-8600 was notably faster than the first Itanium Merced (2001) from HP and Intel at higher clockrates, which in turn were much stronger in floating point (50%).

HP PA-8700 PA-RISC were fast 64-bit CPUs in the early 2000s at a time when competitors started increasing clock speeds for more performance. PA-8700 were in the same ballpark as higher clocked UltraSPARC III (2001), Alpha 21364 (2001) and IBM POWER4+ (2003), faster than Pentium III Xeon (1999) and almost even with MIPS R14000 (2001).

The first Itanium Merced (2001) from HP and Intel was notably much slower than PA-8700 in integer but on par in floating point, while the second generation Itanium McKinley (2002) was faster with more than double the floating point performance.

PA-8800 was a very fast RISC processor when released in 2004, few formal SPEC benchmark scores exist. It was much faster at the same clockspeed than Alpha 21364 (2001), IBM POWER4+ (2003), Itanium McKinley (2002), in the same ballpark of AMD Athlon XP (2002), Intel Xeon (2003) and Pentium 4 Prescott (2003) at much higher frequencies.

Based on PA-8800 performance figures, PA-8900 was possibly a pretty quick CPU for 2005, faster at the same clockspeed than Alpha 21364 (2001), IBM POWER4+ (2003) and Itanium McKinley (2002). Contemporaries such as AMD Athlon XP (2002) and Intel Xeon (2003) had similar performance at much higher frequencies, AMD Opteron (2005) was faster.

Typical SPEC scores of HP PA-RISC computers
Processor Clock Year SPEC95
int  fp		 SPEC2000
int  fp
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
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   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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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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PA-RISC all

Aggregated PA-RISC scores for all PA-RISC processors
Processor Clock Year SPEC89 SPEC92
int  fp		 SPEC95
int  fp		 SPEC2000
int  fp
NS-1 30 MHz 1987 10
PRISM 18 MHz 1988 19
PA-7000 50 MHz 1991 49 31 47 1.20 2.00
PA-7100 75 MHz 1992 107* 82 127 1.53 2.46
PA-7150 125 MHz 1992 182* 136 201 3.97 4.61
PA-7100LC 100 MHz 1994 117 144 3.76 4.06
PA-7200 120 MHz 1995 167 269 6.06 8.14
PA-7300LC 180 MHz 1996 200* 275* 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-8500 440 MHz 1998 31.80 52.40 313 321
PA-8600 552 MHz 2000 42.10 64.00 432 433
IA64 Merced 800 MHz 2001 365 610
PA-8700 750 MHz 2001 57.60 85.90 604 576
IA64 McKinley 1.0 GHz 2002 807 1422
IA64 Madison 1.5 GHz 2003 1315 2106
PA-8800 1.0 GHz 2004 1001
PA-8900 1.1 GHz 2005

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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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