Editing Acorn Archimedes (section)

=== Performance ===

[[File:Archimedes performance.svg|thumb|upright=2|Performance evolution of the Archimedes and various competitors]]

Acorn's original claims for the Archimedes noted a performance of 4 million instructions per second (MIPS), these reportedly being equivalent to DEC [[VAX-11/750]] instructions.<ref name="australianpc198708_newsprint">{{ cite magazine | url=https://archive.org/details/1987.08-australian-personal-computer/page/5/mode/1up | title=Newsprint | magazine=Australian Personal Computer | date=August 1987 | access-date=26 June 2022 | last1=Kewney | first1=Guy | pages=12 | quote=Acorn rates it at four million instructions per second (MIPS), and the instructions we are counting are not the little ARM instructions, but the equivalent of the instructions of a DEC VAX-11/750, the company says.}}</ref> With the VAX-11/750 rated at {{nowrap|0.62 [[VUPS|VAX MIPS]]}},<ref name="dhrystone_data"/> Acorn's claimed {{nowrap|4 MIPS}} translates crudely to around {{nowrap|2.5 VAX MIPS}}. However, the initial {{nowrap|8 MHz}} Archimedes 310 model achieved around {{nowrap|2.8 VAX MIPS}}, delivering competitive performance against more expensive contemporary personal computers such as the {{nowrap|16 MHz}} [[Compaq Deskpro 386]] (priced from $6,499 including 40&nbsp;MB hard drive<ref name="byte198702_386">{{ cite magazine | url=https://archive.org/details/byte-magazine-1987-02/page/n248/mode/1up | title=The ALR Access 386 and the Compaq Deskpro 386 | magazine=Byte | date=February 1987 | access-date=29 April 2022 | last1=Wszola | first1=Stanley J. | last2=Franklin Jr. | first2=Curtis | pages=215–219 }}</ref>), with the Compaq achieving around {{nowrap|2.1 VAX MIPS}}.<ref name="pountain198710" /> (A VAX-11/780 running [[VAX/VMS]] 4.2 produced the baseline [[Dhrystone]] score of 1757 corresponding to {{nowrap|1 VAX MIPS}},<ref name="mips1988">{{ cite tech report | url=http://www.bitsavers.org/pdf/dec/prism/memos/880530_Cutler_PRISM_vs_MIPS.pdf | title=Performance Brief Part 1: CPU Benchmarks | publisher=MIPS Computer Systems Inc. | date=May 1988 | access-date=28 September 2021 | pages=12 }}</ref> this also being used to calculate MIPS ratings for Dhrystone 2 benchmark results.<ref name="dhrystone_intro">{{ cite web | url=https://netlib.org/performance/html/dhrystone.intro.html | title=dhrystone | website=PDS: The Performance Database Server | last1=Aburto | first1=Alfred | access-date=8 October 2022 }}</ref>)

This level of performance made the Archimedes one of the most powerful home computers available during the late 1980s and early 1990s, with its CPU outperforming the [[Motorola 68000]] found in both the cheaper [[Amiga 500]] and [[Atari ST]] machines as well as the more expensive [[Mac (computer)|Macintosh]] and [[Amiga 2000]]. Although an {{nowrap|8 MHz}} 68000 has a performance rating of around {{nowrap|1.2 VAX MIPS}},<ref name="68k-faq">{{ cite web | url=http://www.ee.ualberta.ca/archive/m68kfaq.html | title=comp.sys.m68k Frequently Asked Questions (FAQ) | date=30 September 1995 | access-date=24 August 2021 | issue=20 | last1=Boys | first1=Robert | archive-url=https://web.archive.org/web/19970606025358/http://www.ee.ualberta.ca/archive/m68kfaq.html | archive-date=6 June 1997 }}</ref> the 68000-based [[Amiga 1000]] reportedly achieved around {{nowrap|0.54 VAX MIPS}} when benchmarked as a system.<ref name="dhrystone_data">{{ cite web | url=http://www.netlib.org/performance/html/dhrystone.data.col0.html | title=dhrystone | website=PDS: The Performance Database Server | last1=Aburto | first1=Alfred | access-date=30 September 2021 }}</ref> In comparison, systems based on the {{nowrap|8 MHz}} [[ARM architecture#ARM2|ARM2]], such as the BBC A3000, benchmarked from {{nowrap|2.7 VAX MIPS}}<ref name="chrisacorns_performance">{{cite web |url=http://chrisacorns.computinghistory.org.uk/Performance.html |title=RISC OS Performance Page |publisher=Centre for Computing History |date=31 October 2008 |access-date=18 April 2021}}</ref> up to {{nowrap|3.4 VAX MIPS}}, depending on the operating system version and display configuration.<ref name="stardot_benchmarks">{{ cite web | url=https://stardot.org.uk/forums/viewtopic.php?p=286141#p286141 | title=Benchmarks | website=stardot.org.uk | date=6 May 2021 | access-date=24 August 2021 | last1=Walker | first1=Sarah }}</ref>

Performance improvements would be delivered over time for the Archimedes and its competitors. For example, the Compaq Deskpro 386/16 model was replaced in 1988 with a 386/20 model offering somewhat improved CPU performance (around {{nowrap|3.5 VAX MIPS}})<ref name="byte1989ibm_benchmarks">{{ cite magazine | url=https://archive.org/details/eu_BYTE-1989-fall-6-IBM_special_OCR/page/n56/mode/1up | title=Benchmarks at a Glance: 1989 | magazine=Byte | date=Fall 1989 | access-date=29 April 2022 | last1=Diehl | first1=Stanford | pages=49–53 }}</ref><ref group=note>The 2.1 VAX MIPS of the 386/16 scaled by the CPU performance of the 386/20 divided by that of the 386/16 relative to the IBM PC/AT: 3.61/2.20.</ref> and in 1989 by a 386/33 model improving CPU performance still further (to around {{nowrap|6.6 VAX MIPS}}).<ref name="personalworkstation199005_deskpro">{{ cite magazine | url=https://archive.org/details/sim_personal-workstation_1990-05_2_5/page/n70/mode/1up | title=Great Performers | magazine=Personal Workstation | date=May 1990 | access-date=24 April 2023 | last1=Varhol | first1=Peter D. | pages=65–66 }}</ref> Upgraded Amiga models also offered steadily improving performance, with the Amiga 2500/20 appearing in 1988 and the Amiga 2500/30 appearing in 1989, these delivering approximately {{nowrap|1.5 VAX MIPS}} and {{nowrap|3.0 VAX MIPS}} respectively,<ref name="amigahwdb_benchmarks">{{ cite web | url=http://amiga.resource.cx/perf/aibbde.html | title=Amiga Intuition Based Benchmarks | website=Amiga Hardware Database | date=7 April 2018 | access-date=13 October 2022 }}</ref> with an Amiga 2000 upgraded to a {{nowrap|33 MHz}} [[Motorola 68030|68030]] processor achieving a performance rating of around {{nowrap|3.0–3.6 VAX MIPS}}.<ref name="dhrystone_data" /><ref group=note>Approximate figures for the 2500 models are calculated by taking {{nowrap|0.54 VAX MIPS}} as representative for the Amiga 2000 and scaling it according to the relative performance given for each model's Dhrystone benchmark result in the Amiga Intuition Based Benchmark results, these being 2.80 for the A2620 (Amiga 2500/20) and 5.51 for the 25&nbsp;MHz A2630 (Amiga 2500/30).</ref> The [[Macintosh II]] series incrementally improved their performance from around {{nowrap|1.6 VAX MIPS}} in 1987 with the original 68020-based model, through to around {{nowrap|6.1 VAX MIPS}} in the 68030-based [[Macintosh IIfx]] in 1990.<ref name="byte199009_thompson">{{ cite magazine | url=https://archive.org/details/byte-magazine-1990-09/page/n182/mode/2up | title=The Mac at 40 MHz | magazine=Byte | last1=Thompson | first1=Tom | date=September 1990 | access-date=20 May 2023 | pages=162–164 }}</ref>

The increasing performance deficit relative to the [[x86]] architecture was somewhat reduced with the introduction of the ARM3 in 1990: an Archimedes system such as the A410/1 upgraded to use a {{nowrap|25 MHz}} ARM3 could achieve {{nowrap|10.5 VAX MIPS}},<ref name="stardot_benchmarks" /> with the ARM3-based A5000 achieving a reported {{nowrap|13.8 VAX MIPS}},<ref name="dhrystone_data" /> rising to {{nowrap|15.1 VAX MIPS}} in its {{nowrap|33 MHz}} variant.<ref name="stardot_benchmarks" /> ARM3 upgrades were initially rather expensive<ref name="acornuser199002_arm3" /> but decreased significantly in price and were available for all ARM2 systems, even the relatively inexpensive A3000.<ref name="acornuser199211_simtec" /> Thus, Acorn's ARM3-based machines, generally priced for business or institutional users, remained broadly competitive. Acorn's low-end A3010, fitted with an ARM250 processor, was capable of delivering from {{nowrap|3.1 VAX MIPS}}<ref name="chrisacorns_performance" /> up to {{nowrap|5.0 VAX MIPS}},<ref name="stardot_benchmarks" /> remaining competitive with upgraded Amiga models such as the Amiga 2500.

With development of ARM technologies having been transferred to ARM Limited as a separate company, the performance advantages of Acorn's ARM-based computers, maintained by the transition from the ARM2 to ARM3, eroded somewhat in the early 1990s relative to competitors using processors from established vendors such as Intel and Motorola, as new ARM processors gradually arrived offering more modest performance gains over their predecessors. With ARM Limited focusing on embedded applications, it was noted that "the large performance lead Arm2 and Arm3 once enjoyed" over contemporary Intel processors was over, at least for the time being.<ref name="acornuser199209_upinarms">{{ cite magazine | url=https://archive.org/details/AcornUser122-Sep92/page/n104/mode/1up | title=Up in Arms | magazine=Acorn User | date=September 1992 | access-date=2 October 2021 | last1=Burley | first1=Ian | pages=103–105 }}</ref>

The introduction of the 68040, and particularly the introduction of the 80486 with its subsequent evolution, put ARM3-based Archimedes models at an increasing performance disadvantage. Successors to the Macintosh II in the form of the Quadra and Centris series improved performance two- to four-fold over earlier models.<ref name="macworld199310_av">{{ cite magazine | url=https://archive.org/details/MacWorld_9310_October_1993/page/n87/mode/2up | title=The AV Macs | magazine=MacWorld | last1=Heid | first1=Jim | date=October 1993 | access-date=21 May 2023 | pages=88–95 }}</ref> An Amiga 4000 with 68040 CPU (or a suitably upgraded Amiga 2000 and 3000) could achieve a reported {{nowrap|18.7–21.6 VAX MIPS}},<ref name="dhrystone_data" /> whereas Compaq Deskpro 486/25 and 486/33 models achieved a reported {{nowrap|14.7 VAX MIPS}} and {{nowrap|19.2 VAX MIPS}} with 25&nbsp;MHz and 33&nbsp;MHz 80486 CPUs respectively,<ref name="personalworkstation199104_performance">{{ cite magazine | url=https://archive.org/details/sim_personal-workstation_1991-04_3_4/page/68/mode/2up | title=Great Performance from Both CISC and RISC | magazine=Personal Workstation | date=April 1991 | access-date=8 October 2022 | pages=68, 70–71 }}</ref>{{rp|pages=70}} and with the introduction of 486DX2 CPUs at 50&nbsp;MHz and 66&nbsp;MHz during 1992 raising this to as much as around {{nowrap|28.5 VAX MIPS}}.<ref name="dhrystone_data"/> Against such performance ratings only Acorn's [[Risc PC]] 600 ({{nowrap|18.4 VAX MIPS}}<ref name="dhrystone_data" /> to {{nowrap|21.8 VAX MIPS}}<ref name="stardot_benchmarks" />) fitted with an ARM610 CPU could keep up. However, by the time of its introduction in 1994, two years after the reported incorporation of the ARM610 in the [[Apple Newton]],<ref name="byte199207_apple">{{ cite magazine | url=https://archive.org/details/byte-magazine-1992-07/page/n143/mode/1up | title=Apple ARMs Itself | magazine=Byte | last1=Redfern | first1=Andy | date=July 1992 | access-date=10 October 2022 | pages=134 }}</ref> such performance had already been surpassed by [[Pentium]]-based models such as the Compaq Deskpro 5/66M Model 510 delivering {{nowrap|40.3 VAX MIPS}}.<ref name="apc199307_heavyweight">{{ cite magazine | url=https://archive.org/details/apc-1993_07/page/138/mode/2up | title=Heavyweight contenders | magazine=Australian Personal Computer | date=July 1993 | access-date=8 October 2022 | last1=Crabb | first1=Don | pages=138–140, 142, 144, 146, 149–151, 153–154, 156, 159–160, 162–164, 166, 168, 171–172 }}</ref>

Although the Archimedes, emulating floating-point arithmetic instructions in software, achieved [[Whetstone (benchmark)|Whetstone]] benchmark results comparable to Acorn's earlier Cambridge Co-Processor product based on the 6&nbsp;MHz NS32016 CPU with NS32081 floating-point unit,<ref name="abcomputing198709_aiminghigh">{{ cite magazine | title=Aiming High | magazine=A&B Computing | last1=Taylor | first1=Gordon | date=September 1987 | pages=58–62 }}</ref> such levels of performance were rather less impressive in comparison to contemporary systems equipped with hardware floating-point support, merely reaching a performance level "within a factor of two or less" of [[IBM PC/AT]] systems equipped with a 80286 CPU and [[X87#80287|80287 floating-point co-processor]].<ref name="abcomputing198802_archimedesreport">{{ cite magazine | title=Archimedes Report | magazine=A&B Computing | last1=Taylor | first1=Gordon | date=February 1988 | pages=80–84 }}</ref> Already in 1988, a 20&nbsp;MHz Compaq system with a 80386 CPU and 80387 co-processor would achieve around {{nowrap|1800 KWhetstones}} or around 20 times the performance of the ARM2 emulating floating-point instructions.<ref name="byte198803_80387">{{ cite magazine | url=https://archive.org/details/byte-magazine-1988-03/page/n232/mode/1up | title=The Intel 80387 vs. The Weitek 1167 | magazine=Byte | last1=Thompson | first1=Tom | date=March 1988 | access-date=20 November 2022 | pages=205 }}</ref> Acorn's WE32206-based [[Floating Point Unit]] (FPU), available for the A400 series and R140, was expected to deliver ten-fold performance benefits,<ref name="abcomputing198709_aiminghigh"/> and was eventually claimed to offer eight-fold speed-ups.<ref name="riscuser198912_fpu"/> This left FPU-equipped systems delivering around half the performance of accelerated 386-based systems.

The claimed performance of Acorn's Floating Point Accelerator (FPA10), available for ARM3-based Archimedes systems, was originally 5&nbsp;MFLOPS,<ref name="acorn_fpa10"/> subsequently revised to "around 4&nbsp;MFLOPS",<ref name="acornuser199308_fpa"/> and may ostensibly have been broadly competitive with the MIPS R3010 (as claimed by ARM) in some systems under [[Benchmark (computing)|benchmark testing]], with an A5000 fitted with FPA10 reportedly achieving around 4.3&nbsp;MFLOPS, compared to various R3000/R3010-based systems achieving between 5.4 and 9.7&nbsp;MFLOPS.<ref name="flops_data">{{ cite web | url=http://performance.netlib.org/performance/html/flops_4.data.col0.html | title=Flops_4 | website=PDS: The Performance Database Server | last1=Aburto | first1=Alfred | access-date=24 April 2022 }}</ref> However, unlike the R3010, announced in 1988 with claimed performance ratings of 4&nbsp;MFLOPS for double-precision arithmetic and 7&nbsp;MFLOPS for single-precision arithmetic,<ref name="unixreview198805_mips">{{ cite magazine | url=https://archive.org/details/sim_unix-review_1988-05_6_5/page/107/mode/1up | title=MIPS Rolls RISC | magazine=Unix Review | date=May 1988 | access-date=24 April 2022 | pages=107 }}</ref> and available in workstation products the same year,<ref name="electronicnews19881010_4d">{{ cite magazine | url=https://archive.org/details/sim_electronic-news_1988-10-10_34_1727/page/n11/mode/1up | title=Si Graphics Offers $16K 4D Station | magazine=Electronic News | date=10 October 1988 | access-date=24 April 2022 | pages=12, 16 }}</ref> the FPA10 was eventually delivered in 1993, by which time numerous subsequent MIPS products had been delivered with steadily increasing performance, diminishing the relevance of comparisons with the R3010. For example, the MIPS R4400, available from 1992, achieved around {{nowrap|26 MFLOPS}} when benchmarked in systems. In contrast with the declining competitive situation of the ARM3, the ARM3 and FPA10 combination did appear to rather more competitive with the 486DX2 systems introduced in late 1992, these rated at around {{nowrap|4–5 MFLOPS}}, but a year later these would be eclipsed by the performance of Pentium-based systems starting at {{nowrap|11 MFLOPS}}.<ref name="flops_data"/>