In Parts One And Two of this review of the Scan Computers 3XS FWX99 PowerDAW Windows PC, I looked at the makeup of this system in detail, exploring the reasons for the specification in detail, then running a series of stress tests on this system, against other systems, including a Mac Book Pro.

Find Me A Cheese-grater Replacement!

This part and indeed this entire review series was inspired by a message I received earlier this year, from a good friend of mine who happens to be a multi-BAFTA award winning rerecording mixer. He was trying to equip a new studio and also upgrade from his existing "Cheese-grater" Mac Pro, but retaining the PCIe slots necessary for his HDX2 rigs, plus ensuring future proofing and user serviceability. Unfortunately sticking with Apple meant a cost of £6000 per system, which even such a successful mixer could not contemplate. He set me the challenge to find an equivalent or better performing Windows system, that he could simply replace his Mac Pro machines with.

In the first two parts of this review I've shown how good the 3XS FWX99 PowerDAW is in the native domain, but the average size of session that he regularly runs - 400+ tracks for 5.1 TV Drama, exceeded the (software locked) capabilities of Pro Tools HD (Software Only). He also gets approached to do Atmos versions, so needed HDX MADI IO capability.

Loading Up With DSP

As luck would have it, the 3XS PowerDAW I have for review, has two spare PCIe slots, so I took a trip into town with this system to a friendly reseller, who was prepared to lend me a pair of HDX cards and was actually intrigued to see how well this Windows system performed, compared to the usual Avid qualified HP systems (such as the one now owned by James Ivey).

Luckily the spare PCIe slots were numbers 2 & 3 - any other slots and we could have run into issues with the amount of case space required to host the full length HDX cards. The only little physical issue we hit was that when the case was arranged "portrait" style, the HDX cards sort of "hung down" a bit, which looked more alarming than it actually was, but also brought the risk of solder connections on one card shorting against the heat shield of its neighbour. We ended up using the Avid power connector to keep the two cards straight. This obviously would not be good if the system gets moved around a lot, or is in a mobile setup. This is a case choice issue. I'm certain that if you discussed this with Scan, they would be able to find a good solution for you. Indeed if this was horizontally rack mounted, this would not be an issue at all.

Share Your PCIe Lanes

While the X99-A is an incredibly capable motherboard platform, it is not a typical "server platform", which is more like the HP machines. These machines have more available PCIe slots than the X99-A. This brings with it a couple of possible issues. When you have more PCI devices than slots - don't forget that M2 drives and Thunderbolt connections are technically PCI devices - you end up having to choose which PCIe slots you use for which devices, based on which devices need to share which "lanes". So on this system, it was best for the Thunderbolt card to be in slot 4, but also the M2 system drive shares a lane with slot 3, which had the second HDX card installed. However, the HDX card and M2 seemed happy to share that lane. Avid HDX cards are designed to be adjacent to each other, especially because of the proprietary jumper cable supplied to connect them together. It is possible to reverse engineer that connection using a SATA cable, in order to mount second or third card in non adjacent slots, but as with a lot of these things, it is not supported by Avid.

Digital Signing

This is where we hit our first snag. Windows 10 was seeing the two HDX cards, but an exclamation mark was coming up when looking at the system configuration in Device Manager and Pro Tools would not recognise the HDX cards properly. This is because the Avid drivers' digital signing was not up to date.

This isn't a problem with Windows, or the hardware, but with Avid's drivers and their collaboration with Microsoft. In more recent times, more secure operating systems like Windows 10 and more secure BIOS software, including the newest UEFI boot systems, require devices and drivers to be digitally signed. This is a necessary security measure.

After a long chat with my reseller friend and with Scan Computers, we worked out the best way to sort it out. First we had to open the BIOS utility, which involved holding down the DEL key while booting up the system. We then had to select the advanced menu, go into "Secure Boot", and instruct the boot manager to behave as if it was using an operating system other than Windows 10.

People used to OS X will probably recoil in horror at seeing something so technical. Be assured though that it is completely mouse driven, and is full of help and hints. There is even an "E-Z" (for the UK audience that's pronounced "Easy") Mode. My multi-award winning friend heard that we'd had to do some tweaking, but he was of the opinion, "well, at least you can do it".

A Few Reboots Later...

We had Pro Tools HD happily seeing the two HDX cards -

So I loaded up my own Post Production Stress Test Session (from part two of this review), with the following result -

It was then I noticed something really interesting. When I first fired up the session using the HDX playback engine, it seemed to automatically switch off Dynamic Plug-in Allocation. This had the effect of actually increasing the Native system load to 25% - 9% higher than without the HDX card. This really didn't add up to me, but once we realised and re-enabled the feature, normal service was resumed. However, despite farming out a lot of load to the HDX DSP, the Native system usage never dropped below what it was without the DSP. This is because some supposedly "DSP" plug-ins actually work in a sort of hybrid mode, sharing duties with the Native processing engine. This goes to further show how important it is to have a powerful host system, even if you have a lot of DSP installed.

Do You Really Need HDX?

What was really striking though, was that a Pro Tools session that only used 16% of the available Native processing, used the equivalent of roughly 80% of the HDX card's processing capability. Going by these figures and using some very rough maths, this means that the onboard native processing on this Scan 3XS PowerDAW PC is equivalent to FIVE HDX cards. That's just staggering. It kind of also makes a complete mockery of the Avid software imposed track count limit and IO limit.

Replacing An Existing System

Replacing the existing system with the 3XS was a simple process of disconnecting the old system and re-plugging all the connectors to the 3XS system. Apart from the driver signing issue and having to update Eucon, this was a complete breeze, and the proof can be seen above. The system hooked up to the S3, the Pro Tools Dock, the PT Control app and even the DAD AOIP interface effortlessly and in no time we had the 5.1 mix playing back perfectly, complete with HD pictures from the Blackmagic card.

Thunderbolt 3

With all these PCIe slots available, you may wonder why you also need Thunderbolt? This would come into its own if you ever needed to drop your system into an existing Mac Pro (trashcan) based system. Using a £30 Thunderbolt 3 male (USB-C) to Thunderbolt 2 female (miniDP) adapter, we were able to connect to a Sonnet Echo Express III Thunderbolt 2 chassis, that had two HDX cards installed. It worked perfectly with identical results to having the cards within the box.

This shows the sheer flexibility of this system. Gone are the days when you would have had to scrabble round for the correct connectors, then try and download a bunch of probably non-existent drivers. This is the epitome of the phrase, "plug'n'play". Even though Avid have still not qualified Thunderbolt on Windows, this is total proof that it can and does work.

Conclusion

Reviewing this system has been one of the most enjoyable experiences ever. Never before have I felt so supported when trying to push forward the boundaries of Pro Tools on Windows. A lot of this is down to the excellent support from Scan Computers, who were more than willing to help me push the envelope somewhat and step beyond what Avid claim to be possible, and indeed supported.

There is still an element of risk involved, but at these prices, with this performance, I would encourage anyone to take this step. As long as you approach it with the correct mindset, there's no obstacle to you achieving blistering performance along with excellent value for money and future-proofing. With Scan Computers by your side you can't go far wrong.

The machine reviewed is a Scan Computers 3XS FWX99 PowerDAW, the full specification of which can be found in part one of this review. The cost, including delivery, at the time of writing was £2600.

Looking (Even Further) To The Future

Since beginning this review series, the new Intel i9 processors and X299 motherboards have been announced. Actual models are still thin on the ground, but will be available to order soon. 

As always, we'll try to keep you bang up to date with all the latest developments.