RISC World

Beyond the StrongArm RiscPC

Andrew Rawnsley looks at StrongARM cards.

For more than 3 years now, the StrongArm RiscPC has been the fastest, smoothest and most productive way of running RISC OS, and the applications which you know and love. In the last few months, this has changed, with two new products offering upgrade-starved StrongArm owners something to spend their hard-earned money on. This is in addition to the appearance of RISC OS 4 last year, which again boosted performance, and we‘ll speak more of that later.

The two products - Castle‘s Kinetic StrongArm board and APDL‘s Turbo StrongArm upgrade - are priced very differently, and are ultimately designed to attract different customers. Given RISC World‘s connection with APDL, it is possibly worth clarifying the "neutrality" of this article. The review was written at the behest of the Editor and both the Turbo and the Kinetic have been bought at standard prices. As such, the only input that APDL have had is to take the order for the upgrade!

We‘ll look at the two cards individually (prices of nearly £400 and around £40 don‘t really bear direct head-to-head comparison!) and then draw conclusions on them both at the end.

Castle‘s Kinetic StrongArm board

When Acorn designed the RiscPC, it was built around a 33Mhz Arm610 processor, with the possibility of upgrading to a 40Mhz Arm710 in the future. As such, the rest of the computer was designed to work well within those parameters. Memory was chosen to be the then-industry-standard SIMM memory, which at the time had an access time of around 80+ ns, and to be accessed through a relatively slow memory bus. In order to improve screen performance, dedicated VRAM was used.

Several years down the line, we are using processors up to 8 or 9 times faster than those originally intended, yet the memory system is limited to exactly the same performance it was back in the early 1990s. This leads to a number of bottlenecks, and the aim of the Kinetic card is to alleviate these. It does so by utilising modern (8ns compared with 80+!) SDRAM memory, in the form used by many portable PCs these days, and a 64Mhz processor to memory bus. Don‘t worry if that doesn‘t mean much to you, but suffice to say that it significantly more up to date than what you have already!

Quite clearly, the best way to achieve this would be to design a new computer from scratch, but that would add to the expense, and also rely on major updates to RISC OS. Instead, the Kinetic card is a half way house, coupling this advanced memory system with a 233 rev T StrongArm on a single (large!) processor card for existing RiscPC owners.

The board fits tightly inside the machine left-to-right, so you‘ll need to strip it down to its base to plug it in properly. The card includes 64Mb of RAM on a standard connector, but as there is only one such connector, any future upgrades will make this 64Mb redundant. A new version of RISC OS 4 is also included (confusingly the version number is 4.03 as with the RiscStation and Mico, but the core of the OS is very different) and you will need to install this at the same time in order to use the Kinetic card. The whole process is much the same as installing the original StrongArm card, although the larger size makes the logistics a bit more complex. I would anticipate that most people would find fitting it straightforward, but using a dealer or Authorised Installer would seem prudent if you aren‘t completely happy with the idea.

So, how does it perform? Castle claim around 3 times performance increase, although admit that this doesn‘t always apply. In my experience that figure is a little hopeful, but there is certainly no question that this is the fastest upgrade you can currently buy for your RiscPC. Personally, I don‘t hold a lot of stock in benchmark figures, as statistics can be used to prove anything. I‘m writing this review now on the Kinetic machine (it also has the largest screen connected to it!) and it is certainly a smooth ride; but so was a standard 233Mhz StrongArm. You see, 90% of RISC OS software is written to perform well on 610/710 class machines, so the benefits are less tangible the faster you go.

The most demanding tasks such as graphically-intensive printing, work in Photodesk, complex web page rendering and the like are noticeably faster, but not hugely so. In many respects, the performance increase from an existing 233 RO4 machine is like that of going from RISC OS 3.x to RISC OS 4 - about 50%. It is important to realise that this is coming exclusively from the faster memory, as the StrongArm on the card is still clocked at 233Mhz (and there appeared to be no obvious way of overclocking).

The biggest sustained performance increase I observed was in Quake, which ran up to 60% faster, and critically reached the "sweet spot" where playing felt smooth rather than slightly jerky. As for other tasks, I have generally found myself gravitating to web browsing on the Kinetic machine, but the larger screen helps there too.

However, comparing a Kinetic card with a standard StrongArm is doing it a disservice. Whilst I suspect most people who can afford the Kinetic will probably have a StrongArm card already, the real appeal of the board is for those without. The Kinetic pack includes everything you could want for rejuvenating an aging machine - RISC OS 4, plenty (64Mb) of memory, and a fast StrongArm to boot. If you are still using a largely unexpanded RiscPC 600 or 700, then this must be a very attractive proposition.

There are inevitably a couple of downsides to the Kinetic - nothing is ever quite perfect. The single biggest fault of the Kinetic is that podules using DMA will revert to slow, non-DMA mode when the Kinetic card is installed, as the version of RISC OS 4 lacks appropriate changes to allow DMA to work with the Kinetic‘s SDRAM. In most cases, the performance hit is not huge - it is usually hard disc interfaces using DMA, and RISC OS is not as hard drive intensive as some other operating systems we could mention - but it is there. I would imagine that those involved with video-editing tasks where disc performance is critical, would not be happy to learn that their interfaces were running at half speed. Note that a tiny minority of cards may fail altogether if DMA isn‘t available. If you are using a SCSI or IDE card, you should check with your supplier for advice.

The second slight marring is that any existing RAM you have becomes largely redundant. Whilst the system will make use of it (indeed, it is necessary for the PC card) it is only used when the 64Mb on the Kinetic is used up. This is, of course, a "good thing" in that you don‘t want your system reverting to slower memory unless absolutely necessary, but most users will never need more than 64Mb to run RISC OS software, making the extra RAM feeling like a spare part.

Castle‘s MD once said to me "charge a premium price for a premium product", and that really does apply to the Kinetic card. At around £400 inc, it is not a cheap upgrade, especially for existing StrongArm owners who qualify for just a £50 reduction. Similarly, RISC OS 4 owners receive a mere £50 off, compared with the £120 spent recently! There is no question that the Kinetic is the fastest current upgrade, but I wonder if it is priced at just a little too much of a premium for most users. It seems to me that there is a checklist of questions which you should ask yourself:

  • 1. Do I already own a StrongArm?
  • 2. Do I already own RISC OS 4?
  • 3. Do I already have plenty of memory?

If the answer to two or more of these is "yes", then I would suggest that the Kinetic should be considered something of a luxury, and you may be better to wait for price reductions, new machines or a lottery windfall before purchasing. If you have one "yes", (esp StrongArm) then you may well still want to hold off, but you will find the performance increase worthwhile. If you answered "no" to all of the questions, then the Kinetic becomes almost the "perfect" upgrade, but you may have to dig deep to afford it.

APDL Turbo StrongArm

As many readers may be aware already, the StrongArm cards sold by Acorn, and subsequently Castle, could be overclocked to make them perform faster than specified. Doing this involved careful work including cutting tracks on the PCB, a fan, a bit of knowledge and a very steady hand. Like most people, I shied away from risking this on my StrongArm card - damaging it would be a very expensive mistake!

The APDL upgrade offers a cost-effective and, above all, safe way of boosting the performance of your existing card. This is how the price can be kept so low - the costs to APDL being relatively small. For your money, you will receive a card running at either 275Mhz or 287Mhz (confusingly, the old 200Mhz cards can be clocked higher than the newer 233Mhz cards!) which has been safely upgraded and, crucially, soak-tested for 24 hours before being sent back to you.

The card you receive is, naturally, almost identical to your old one (APDL offer a swap out service, where they send you a new card, and you send them your old one back by return). The APDL card will have grown a small cooling fan, which hooks into one of the computer‘s power cables, and includes a pass-through so you won‘t lose a power lead.

Installation is trivial - just pull out your existing card and insert the new one. The Turbo card works with RISC OS 3.7 or 4, so there is no need to upgrade the operating system at the same time. Once installed, simply power up your machine, and away you go.

The performance of the card reflects the lower price, and APDL make no wild claims, but it is nonetheless well worth having. Again, the computer feels a little smoother, and boots a little faster. In numerical terms, the card broadly lives up to its 25-30% clock speed increase, with the usual web browsing and Quake tests bearing that out.

There is little more to say - there were no noticeable side effects with the card installed, although perhaps I should comment that floppy disc handling on both machines (Turbo and Kinetic) has been a little flaky recently. I think it is unfair to put this down to either processor, and I‘ve been checking some discs on the Turbo earlier today.

If I were living state-side, I‘d be tempted to describe the APDL upgrade as a "no-brainer" - that is to say that the decision is very simple. Whilst you‘ll need to own a StrongArm already, for a very small outlay you get a noticeable speed increase. After several years of owning a 200 or 233Mhz processor, this is a simple and effective method of rejuvenating your system without resorting to feeding it viagra!


It would not be right to produce an article about improving your computer‘s performance without a brief section on RISC OS 4. Whilst other articles have done the "review" angle to death, RO4 is nevertheless an extremely effective way of boosting your machine‘s performance, and getting rather more besides! Installing the operating system will give an immediate cross-the-board increase of between 30 and 50% and whilst its £120 price tag may be rather more than a Turbo StrongArm, you do get a lot more functionality as well.

The Kinetic board includes RISC OS 4 as part of the pack, making it a comprehensive performance boost, whereas with the APDL Turbo upgrade, you will need to buy both. For most people, it will come down to a decision based on what you currently own as to the most cost-effective upgrade.


The two upgrades appeal to different segments of the marketplace, and as such it is unfair to compare them directly. To take advantage of the APDL Turbo upgrade, you will need to own a StrongArm already, and RISC OS 4 has to be purchased separately. However, if the RiscWorld subscriber base matches my own experiences, if you are spending money upgrading your computer, you will probably own one or both of those items already. In this case, justifying the Kinetic becomes quite difficult. If money is no object, then you will probably have bought a Kinetic already. If you are seriously comparing the two upgrades, then the chances are that the £300 to £400 cost of the Kinetic is not realistic. As such, the APDL offering becomes almost mandatory. Sure, it isn‘t as speedy as the Kinetic, but it gives a real boost at a price which is very fair.

There are, however, many people still running Arm 610/710 machines, and for them the Kinetic is much more attractive. We all wish it wasn‘t £400, but you do get a fair bit for your money. It is a side effect of the size of the market that such prices are necessary to cover the costs of development. If you‘re using an older or less expanded machine, then you certainly won‘t be disappointed with the Kinetic. Equally, if you are considering a new machine, a Kinetic RiscPC makes an excellent purchase. But if you‘ve already been upgrading your machine as the other upgrades came along, APDL‘s product perks your system up noticeably, and at the price, you can‘t go wrong!

Product details

Product: Castle Kinetic Card
Supplier: Castle Technology
Price: £468.33 (inc VAT) - upgrades discounts available
Address: Ore Trading Estate, Framlingham, Ip13 9LL
Tel: 01728 723200
Fax: 01728 621179

Product details

Product: APDL Turbo Card
Supplier: APDL
Price: £49 (inc VAT) +£3.50 p&p - (202Mhz to 287Mhz)
Price: £39 (inc VAT) +£3.50 p&p - (233Mhz to 276Mhz)
Price: £29 (inc VAT) +£3.50 p&p - (202Mhz to 257Mhz)
Address: 39 Knighton Park Road, Sydenham, London, SE26 5RN
Tel: 0208 778 2659
Fax: 0208 488 0487

Andrew Rawnsley