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Specifying & Building A Dual-core Desktop PC

PC Musician
By Martin Walker

If you haven't yet taken the dual-core plunge, there's an alternative to either buying an off-the-shelf mainstream model that may not be quite right for music or paying a premium for a custom-assembled music PC: choose the components and build your own.

Specifying & Building A Dual-core Desktop PC

Dual-core PCs have generated more than their fair share of potential problems for the PC Musician, with early chip set audio problems, PCI Express confusions and AMD/Intel performance issues. There's now a wide range of components available, and when I came to build my own dual-core PC there were a lot of choices. So how do you decide which is the best processor, motherboard, case and PSU? There's no such thing as a definitive set of PC parts, but in each category I'll outline the main options and their various strengths and weaknesses, and explain the reasons behind my particular choice.

Dual-core Processor Options

The first and most important consideration is that of processor make and model. This affects your choice of motherboard chip set and therefore provides a motherboard shortlist, which in turn determines the choices for RAM type and amount, and so on. With this in mind, I'll spend the most time discussing the processor choices, then the others should fall into place more easily.

When I last discussed dual-core options in SOS March 2006, there were two main contenders for most of us: Intel's Pentium D range, offering good performance, PCI Express and good compatibility with existing PCI cards; and AMD's Athlon X2, with a few compatibility problems but easier to cool and generally offering better audio performance for a similar outlay. Many PC musicians were tempted by X2-based PCs, and still are, but Intel finally fought back when they released their long-awaited desktop version of the processor that had performed so well in Centrino laptops.

By SOS May 2006, I was extolling the virtues of Intel's dual-core 'Yonah' in their Core Duo laptop models, but when I was writing for SOS September 2006 I was even more excited by the imminent release of Merom, Woodcrest, and Conroe, the second-generation dual-core processor ranges for laptop, server/workstation and desktop use respectively. Although, as with any new processor range, musicians were initially wary until some audio benchmarks had been run, Conroe has proved to be a superb performer that's also far easier to keep cool than its Pentium D predecessors.

My choice of motherboard was an Intel DB965LT, for its proven audio performance, comprehensive selection of three PCI, three PCI Express x1 and one PCI Express x16 expansion slots, plus two onboard Firewire ports.My choice of motherboard was an Intel DB965LT, for its proven audio performance, comprehensive selection of three PCI, three PCI Express x1 and one PCI Express x16 expansion slots, plus two onboard Firewire ports.Meanwhile, AMD introduced a new Socket AM2 format for their processor ranges that supported DDR2 (Double Data Rate) RAM with 30 percent greater bandwidth, and superseded the existing Socket 939 and Socket 754 formats. At the time, I stated that audio performance seemed essentially identical to that of the older AMD Socket 939 format processors, although more recent figures do show that AM2-equipped machines can give you slightly more welly. For instance, an AM2 4200+ processor provides roughly equal performance on some audio benchmarks as an X2 4400+ processor down to 6ms latency, although the Socket 939 version moves ahead at lower latency values.

Those requiring even more powerful machines have two other options to consider: machines featuring a pair of dual-core AMD Opteron processors, and those with a pair of dual-core Intel Woodcrest processors (ie. both run a total of four cores). Both of these latter options can provide blindingly fast performance for those that need it, who generally fall into two camps: musicians who want to run vast numbers of high-powered soft synths and plug-ins; and those who require large numbers of audio tracks and plug-ins and also want to run their sequencers at latencies of 1.5ms, for almost real-time monitoring with plug-in effects.

To give you an idea of the power available on such systems, according to DAW Bench tests (www.aavimt.com.au/dawbench), an AMD dual-core Opteron 280 whose cores run at 2.4GHz can manage a massive 177 plug-ins at 6ms latency (40 EQs, 40 dynamics, one multi-band dynamics and 96 Magneto plug-ins), dropping to 146 at 3ms latency (65 Magnetos) and 124 (43 Magnetos) at 1.5ms latency.

However, while systems based on a pair of Intel's 2GHz Woodcrest dual-core processors have turned in similar results down to 6ms latency, they are pulling significantly ahead at 3ms (96 Magnetos) and 1.5ms (72 Magnetos), making them the current leaders for anyone who wants to record lots of audio tracks and needs to monitor them 'live' with plug-in effects and not experience obvious audio delays. As I write this, quad-core processors are also on the horizon (Intel's Kentsfield, with two Conroe dies mounted on one physical package, will be first, followed by AMD's true quad-core Barcelona), and then octuple-core processors will no doubt follow. However, the vast majority of musicians should be more than happy with a dual-core PC, which will provide the biggest leap forward in processing power that most of us have ever enjoyed.

Dual-core Cost: Pricing

The total cost of any music PC is dependent on the processor, motherboard, amount of RAM, number of drives, and so on you want. My goals when building this PC were good processing performance, very low acoustic noise and bargain price. Here's what I paid (prices include VAT):

CPU, MOTHERBOARD & RAM

  • Intel Core 2 Duo E6600 2.4GHz CPU £209
  • Intel DP965LT motherboard £82
  • 2GB Corsair Twin 2X2048-6400 RAM £187

OTHER COMPONENTS

  • Gigabyte 7300LE 128MB graphics card £37
  • Two Samsung SP2504C 250GB drives £102
  • Pioneer DVR111 DVD burner £23
  • 1.44MB floppy drive £4
  • PaQ 4U 550 Powerful and Quiet Case £140
  • Seasonic S12 430W PSU £40
  • Thermal Right XP120 Cooler/120mm fan £41
  • TOTAL COST: £865

Making The Choice

So which should we be choosing? Well, since the majority of us will be upgrading from a single-core PC, any dual-core system would hit the spot, providing very fast performance compared with single-core machines. For instance, even the cheapest AMD Athlon X2 3800+ CPU model should give you double the processing power of the Pentium 4 2.8GHz machine that I'm currently running.

AMD's X2 range is justifiably still very popular with musicians on a budget, but if you've got a little more money to spend, Intel's Conroe has to be the one to buy for added performance. Conroe-compatible motherboards and RAM also tend to be more expensive, so if you want to fit 4GB or more in anticipation of Windows Vista early next year, AMD starts to look like a stronger contender again, but with the more typical 2GB fitted by the majority of musicians nowadays, the Conroe looks very attractive.

Whatever you decide, the final decision is always which model in your chosen range to buy. As I write this at the beginning of November, prices still seem to be in free-fall, but the most popular Conroe model is definitely the E6600 with 2.4GHz clock speed, retailing at just over £200 including VAT, and this is the one I chose.

How To Choose A Suitable Motherboard

Anyone building a machine with an AMD X2 processor at its heart should be aware that the initial audio pop or click and high CPU overhead problems with single-CPU NForce 4 chip sets haven't completely gone away, but as soon as musicians started to use them with dual-core instead of single-core AMD processors the problems reduced in severity. Various people have now measured NForce 4 audio performance as on a par with previous NForce 3 results down to 6ms latency, although below this a few people are still suffering from clicks or pops and higher CPU loads than expected.

One alternative for those interested in AMD Athlon X2 processors is the ATI Radeon XPress 200 chip set. Motherboards featuring it, such as the Asus A8RMVP, are generally getting good press from the music community (especially since this model features two Firewire ports: many dual-core boards have none). However, MSI boards featuring this chip set do seem to be causing a few audio problems.

If you're building a Conroe-based dual-core PC there are two main choices of chip set: Intel's 965 and 975. Motherboards featuring the 975 chip set tend to be considerably more expensive, and until very recently didn't support high-performance ATI Crossfire graphics. Ironically, this can make them more suitable for musicians, who don't need high-powered graphics cards and often run into audio problems if they insist on fitting them. However, overall, with good performance and lower priced motherboards, the 965 chip set seems to be proving very popular for audio use.

While searching for a suitable 965 motherboard model, I discovered quite a few with just two PCI and two PCI Express slots and no built-in Firewire ports. For a musician, this combination isn't really good enough, because if you ever wanted to use a Firewire audio interface you'd immediately need one of the four slots for a Firewire card, leaving you with little potential for expansion.

I decided to concentrate on 965 motherboards featuring three PCI slots and three PCI Express x1 slots (providing me with good expansion potential), plus a single PCI Express x16 graphics slot. Of these, I ruled out Gigabyte's GA965P S3 and GA965P DS3 for lacking Firewire ports, and ended up with a shortlist of the Asus P5BE and the Intel DP965LT, both of which support up to 8GB DDR2 SDRAM at 800, 667 or 533MHz speeds. Intel's boards have a reputation of being extremely reliable but not so 'overclockable' (increasing the board beyond its rated specification), but I wasn't going to indulge in this black art. In any case, since the Intel model had two Firewire ports compared with the one of the P5B, was £20 cheaper, at just £75, and had already proved popular with other audio specialists, this is the one I ended up choosing.

RAM Considerations

The next consideration is RAM, and with Microsoft's memory-hungry Vista operating system becoming ever more imminent, 1GB must be viewed as the practical minimum. Given the number of software samplers that now use system RAM for buffering, and the fact that some soft synths can gulp 100MB or more for a single patch, if you're serious enough to be investing in a powerful dual-core PC, 2GB of RAM seems a much more sensible option. When Vista is finally released and removes the current RAM ceiling of Windows XP, 4GB or even 8GB will be attractive to some musicians, but given that RAM prices have risen I think 2GB is currently the best bet. Although you can install RAM one stick at a time, you'll get better performance from using matched pairs of modules, so buying two 1GB sticks makes most sense. On most motherboards, that will leave a second pair of memory slots for future expansion.

Many people think that deciding how much RAM to buy is the whole story. Far from it. For instance, some motherboards seem fussy about what RAM they use, and one recurring problem with some models, including Gigabyte's GA965P DS4 and my choice, Intel's DP965LT, is that they supply only 1.8V to the RAM by default. Some RAM prefers a minimum of 1.9V and you won't even be able to get into the BIOS to determine what's wrong in such cases.

Buying RAM can be a confusing business for the novice. On the right-hand side of the Corsair RAM I bought you can see its timing (5-5-5-12), its speed (800MHz) and its capacity (1024MB). See the main text for details.Buying RAM can be a confusing business for the novice. On the right-hand side of the Corsair RAM I bought you can see its timing (5-5-5-12), its speed (800MHz) and its capacity (1024MB). See the main text for details.Most Core 2 Duo motherboards also support DDR2 RAM sticks that run at 533MHz, 667MHz or 800MHz, so RAM speed is yet another consideration, especially as the faster the memory, the more you have to pay for it. The ramifications (sorry about that one) are complex.

In various mainstream benchmark tests, the differences in performance between these three RAM speeds have been measured at two percent or less. However, as always, we're more interested in audio-related performance, and while the popular Thonex audio benchmark often shows little variation in performance with RAM speed, the Blofeld's DSP40 test does seem to indicate that faster RAM lets you run more plug-ins, this effect being magnified when running at latency values of 6ms and below. With this in mind I decided to buy two matched 1GB sticks of 800MHz DDR2 RAM for my new PC.

There's also the further question of CAS (Column Address Strobe) Latency, which is the number of processor clock cycles it takes the memory to respond to an operation request and is generally expressed as a simple number, such as CAS4 or CL4. The lower the number, the faster the RAM will respond, but the more expensive it will be. In general, for a given price I'd recommend buying RAM with a higher MHz speed and a slightly larger CAS Latency, rather than the other way around.

Given all these potentially confusing choices, my advice is to follow any recommendations given for your chosen motherboard on the web site you buy it from (www.scan.co.uk, for instance, place a link labelled 'Recommended Corsair memory' on each motherboard page for the models they stock). Alternatively, visit the web site of one of the major RAM manufacturers, such as Corsair (www.corsair.com) or Crucial (www.crucial.com) and enter your motherboard make and model into their Memory Advisor tools.

The Crucial web site provided me with eight possible 2GB kits for my proposed Intel DP965LT, ranging in price from £150 to £370, but pre-armed with the knowledge that I could probably discard those requiring more than 1.8V and that I wanted DDR2 800, I reduced this selection to just one type at £233. If I'd been happy with the slightly slower DDR2 667, it would only have cost me £154. Corsair recommended three compatible products and I ended up buying Corsair XMS2 DDR6400 (800MHz, CAS5), which cost me £190.

Graphics Cards

As mentioned during my discussion of motherboard chip sets, technologies such as ATI's Crossfire and Nvidia's related Scalable Link Interface (which allow two PCI Express graphics cards in the same computer system to be linked for faster parallel processing of graphics) tend to be counter-productive for an audio PC. You simply don't need such speed for displaying the non-3D screens of audio sequencers, and even graphics professionals working with applications like Adobe's Photoshop won't see any benefits from such high-speed 3D-accelerated graphics cards.

A fast 3D graphics card is a waste of money for most musicians, who instead rely on 2D performance. This Gigabyte model I bought is also passively cooled, so it's totally silent, and it cost me just £37.A fast 3D graphics card is a waste of money for most musicians, who instead rely on 2D performance. This Gigabyte model I bought is also passively cooled, so it's totally silent, and it cost me just £37.Not only will you save money by opting for a modest graphics card instead of a gaming model, but a modest card also provides the musician with two other advantages. First, you'll be able to get one with passive cooling. This eliminates noisy cooling fans — and some of the tiny ones found on fast graphics cards can really produce an annoying high-pitched whine. Second, since a slower graphics card doesn't produce so much heat, your PSU and any other case fans pulling hot air out of your PC into your studio won't need to work so hard, resulting in an even quieter PC.

You'd be foolish to build a PC at the moment without making sure it can run Microsoft's imminent but graphics-hungry Vista operating system. This means a Direct X 9-compatible card with 128MB or more of dedicated graphics RAM. Some models to consider are the ATI Radeon X300SE and the ATI X550 model with 256MB of RAM, or the Nvidia Geforce 6600 GT 128MB or Geforce 7300GT 256MB. Since 256MB is only needed to support monitor resolutions above 1920 x 1200 pixels, I was quite happy to restrict myself to cheaper models with 128MB, and ended up buying a Gigabyte 7300LE model for the very modest sum of £37.

Drives

The other main components to choose are hard drives, optical drives and floppy/multimedia drives. The choice of these is very much down to personal requirements for capacity and features. I've used Seagate Barracuda drives for years and have been very happy with both their performance and acoustic noise, but if you want a large-capacity 7200rpm hard drive with 8MB buffer, both the Western Digital Caviar SE16 and Samsung Spinpoint T-series drives are also currently getting good reviews for their low acoustic noise and high performance.

All three manufacturers offer similar prices for each capacity, and if you do the calculations for a selection of differently sized drives, you'll find that drives of 120GB and below work out significantly more expensive per Gigabyte of storage than larger drives, while the price starts rising again above 400GB. When I checked in mid-November 2006, the 'sweet spot' was 250GB. With the majority of such drives hovering at around the £50 mark, this works out at just 20p per Gigabyte. For my new PC, I bought Samsung SP2504C 250GB drives, since on the day I bought they were slightly cheaper than the competition.

I was going to move the DVD burner from my existing PC across to the new machine, as that already had a CD-R/W drive in reserve, but when I noticed how cheap most new DVD burners now are I bought a black Pioneer DVR111 model for only £23. Although some specialist retailers have abandoned the humble floppy drive, I also bought one of these, at just £4, simply for those rare instances when I might need it to run DOS-based utilities.

Case, PSU & Cooling

Here you can see the unusual interior of the PaQ case, where most of the interior components are a tight press-fit into high-absorption acoustic foam. Towards the rear of the case (the left in this photograph) the motherboard assembly slides into grooves in the case, while beneath the central vertical strip hide three 120mm case fans running in parallel. At top right the optical and floppy drives are a firm push-fit between foam spacers, and at lower right you can see the aluminium heat spreaders that house up to three hard drives, as well as the perforations of the muffler (part of the front door's acoustic labyrinth).Here you can see the unusual interior of the PaQ case, where most of the interior components are a tight press-fit into high-absorption acoustic foam. Towards the rear of the case (the left in this photograph) the motherboard assembly slides into grooves in the case, while beneath the central vertical strip hide three 120mm case fans running in parallel. At top right the optical and floppy drives are a firm push-fit between foam spacers, and at lower right you can see the aluminium heat spreaders that house up to three hard drives, as well as the perforations of the muffler (part of the front door's acoustic labyrinth).Once you've decided on your components, you need a suitable enclosure to house them, a power supply and a CPU heatsink/cooler. For the musician, the low acoustic noise of all these components is a prime consideration, as I discussed in my 'Advanced PC Silencing' feature in SOS April 2006. No one who read that feature will be surprised at my choice of case, since I stated there that I was so impressed by the incredibly low noise of the PaQ case (www.paq.ltd.uk) that I pre-ordered one for my next PC. Since this preview generated a lot of interest from SOS readers and it's so different from most other PC cases, I want to look at the final production version in rather more detail.

The weakest aspect of most PC cases is the amount of drive noise that escapes via the front, even when some sort of hinged door is provided, while many cases rely on several 80mm cooling fans running at speeds over 1000rpm, which often create an annoying high-pitched whine.

The exceptionally low noise of the PaQ case is achieved partly by a total of three 120mm case cooling fans in parallel, running at a significantly lower speed and buried deep within the case where they can't be heard. In addition, all the major components are a press-fit into high-density acoustic foam, which prevents their vibration being transmitted to the rest of the case. Meanwhile, the hinged front door and associated inlet mufflers create an acoustic labyrinth that attenuates any remaining noise from CD and DVD drives.

Some cases have an integral PSU, but many don't, since power requirements can vary so much between users. You can gauge your own requirements depending on the CPU, motherboard, amount and type of RAM, number of hard drives, expansion cards and so on you want in your PC. I discussed this process in PC Notes May 2004 (see 'Further Reading' box). I bought the PaQ 4U 550 case that can be used as a midi tower or desktop, or rackmounted with the optional brackets, and as standard it's fitted with a Seasonic S12 430W PSU (one of the quietest available) with integral 120mm cooling fan.

Here's a close-up of the three case fans (across the top), all embedded into acoustic foam so that their vibration isn't transmitted to the rest of the case. Notice how the red SATA cables fit neatly through slots in the foam.Here's a close-up of the three case fans (across the top), all embedded into acoustic foam so that their vibration isn't transmitted to the rest of the case. Notice how the red SATA cables fit neatly through slots in the foam.Although CPUs are nearly always bundled with a heatsink/fan combo, these are best abandoned on an audio PC, in favour of a more up-market and quieter CPU cooler, which may also reduce the full-load temperature of your processor by 10 or more degrees Celsius. Models that are well worth considering include the Arctic Cooling Freezer 64 Pro, the Scythe Ninja Plus, the Thermal Right MST 9775 and the Zalman CNPS 9500, but given the large size of some modern heatsinks you should always check on their manufacturer's web site that your chosen motherboard will accommodate them without fouling their larger components.

My use of the PaQ case was guided by its designer, Peter Cyriax, who supplies a duct that you slip over the top of the combined CPU, heatsink and fan assembly, with a single exit that connects to the rear of the case. Exhausting the hot air directly to the outside world, rather than re-circulating it inside the case, keeps all the components cooler. The duct obviously needs to be purpose-designed to partner the cooler, and since Peter has achieved particularly good results with the Thermal Right XP120 and yet another slow-spinning 120mm fan, this is the one I bought.

The attractive high-gloss black panels of the incredibly quiet PaQ case are built from 3mm-thick aluminium composite material (for a small extra charge you can order your case in a variety of other colours). Its interior is built almost entirely from high-absorption acoustic foam with an average 10mm thickness.The attractive high-gloss black panels of the incredibly quiet PaQ case are built from 3mm-thick aluminium composite material (for a small extra charge you can order your case in a variety of other colours). Its interior is built almost entirely from high-absorption acoustic foam with an average 10mm thickness.

The Actual Build

I covered all the steps involved in installing a PC motherboard in some detail in SOS December 2003 (see 'Further Reading' box), so I won't repeat them here, except to say that my preferred order is to install the RAM into the motherboard, followed by the CPU and associated cooler, before fixing the motherboard itself into the case. If you do it this way around, you generally get more room to manoeuvre and don't risk flexing the motherboard when applying the downward force required to get most RAM sticks to click into place.

The PaQ case makes this part of the build even easier, since its entire motherboard and back panel sub-assembly slides out of the case, while the USB, Firewire and control cable assembly can also be unplugged from the main part of the case. This means that you can attach your motherboard, RAM, CPU and cooler to its base-plate, plug in all the fiddly USB, Firewire and control header plugs (power and reset switches, plus power and hard drive activity LEDs) while you still have comfortable all-round access, attach the back panel, bolt in your graphics card and any other expansion cards, and then slide the entire finished assembly back into the case.

Fitting the optical and floppy drives into the PaQ case is also easier than normal, since they are a firm press-fit between foam spacing blocks, while the hard drives (up to three 3.5-inch models can be fitted) are bolted into aluminium 'heat spreaders' and can then be easily slid into their foam slots. The various connecting cables running from the front to the back of the case fit neatly into slots in the foam.

Overall, despite a few head-scratching moments due to the unusual build process, my new dual-core PC proved to be both elegant and blissfully quiet! Next month I'll cover the BIOS tweaks, Windows installation and performance aspects of building your own PC. 

Published February 2007