Intel's 8-core Skulltrail Platform: Close to Perfecting the Niche
by Anand Lal Shimpi on February 4, 2008 5:00 AM EST- Posted in
- CPUs
Dual socket motherboards have been around for ages, but dual socket enthusiast motherboards have a far shorter history. Back during the days where instruction level parallelism seemed to have no end in sight, having more than one CPU just didn't make sense for the masses. Most Windows applications weren't multithreaded and CPU prices just weren't what they are today.
Many of the same types of applications that benefit from multiple cores today were still around back then; 3D rendering, animation and image processing were all multithreaded CPU hogs. The problem is that if you wanted more than one CPU you generally had to make a choice between a tweakable, high performance enthusiast motherboard or a workstation board. Workstation motherboards were much more expensive, not nearly as flexible from a component standpoint and hardly ever performed as well as their desktop counterparts - the only real benefits were a more robust design and of course, the ability to support multiple CPUs.
Over the years we saw a few important dual-socket enthusiast motherboards arrive on the scene, the most popular of which was arguably ABIT's BP6. For all intents and purposes the BP6 was a desktop motherboard, it just had two CPU sockets. Intel's Celeron processors were cheap enough where you could pop in a couple, overclock them and have a pretty decent workstation based on an enthusiast desktop motherboard. Tradeoffs? There were none. It was a very popular board.
Times do change and eventually AMD/Intel stopped getting amazing returns from simply increasing instruction level parallelism and clock speed with their CPUs. The two turned to thread level parallelism to carry them through the next decade of microprocessor evolution; seemingly overnight, everyone had multiple cores in their systems.
The advent of the multi-core x86 CPU all but eliminated the need for a dual socket enthusiast platform. If you needed more cores simply toss a multi-core CPU in your desktop board and you were good to go. When Intel introduced the first quad-core desktop x86 processors things got even worse for dual socket motherboards. Most applications have a tough time using more than two cores, a single quad core CPU covered virtually all bases - and they were affordable too.
AMD didn't have a quad-core CPU until the recent launch of Phenom. In order to fill the gap between the dual core Athlon 64 X2 and the delayed arrival of Phenom, AMD dusted off plans to introduce a dual socket enthusiast platform and called it Quad FX.
The idea was simple: build an enthusiast platform that used normal dekstop components but had two sockets. With dual-core CPUs this meant that you'd have four cores in a system, and when quad-core arrived you'd have a healthy 8, all on an enthusiast class motherboard.
Quad FX was abandoned by AMD (although it does promise an upgrade path to quad-core CPUs), largely because while you had to buy an expensive motherboard and two dual cores to put the Quad in Quad FX, Intel was shipping faster, single socket, quad-core CPUs.
Intel did see some merit in AMD's Quad FX platform and actually released an ill-prepared competitor, something it called V8. Intel basically took a workstation Xeon motherboard and recommended enthusiasts purchase a pair of quad-core Xeon processors, giving you an 8-core alternative to Quad FX. The problem with the V8 platform was that it was expensive, there was no multi-GPU support and it required expensive FB-DIMMs thanks to its Xeon heritage.
The original V8 board was straight from the server world
Last April, Intel announced that it would be releasing a successor to V8, codenamed: Skulltrail. Designed to fix many of the problems with V8, Intel kept its promise to release the platform despite AMD's abandonment of the Quad FX project.
Today we have a preview of Skulltrail, which Intel expects to make available this quarter. Unlike Intel's Centrino or vPro, Skulltrail isn't officially a "platform" it's just a name for a motherboard and CPU combination, nothing more. The motherboard is the Intel D5400XS, based on Intel's 5000 series server/workstation chipset (yes, FB-DIMMs are still a requirement). The board supports any LGA-771 CPU, but Skulltrail is designed to be used with a new processor: the Core 2 Extreme QX9775.
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moiettoi - Friday, June 27, 2008 - link
Hi allThis sounds like a great board and for some-one like me that uses 4x22"monitors and does heaps of multi tasking it sounds perfect and would gladly pay the price asked.
BUT why is such a great board slowed right down by not having DDR3 memory sticks,,,because from what I've read at the momment there is not that much difference with running this and what I have now which is a quad core with DDR3 which runs great but I do overwork it.So bigger would be better.
You would think and I'm sure they already know that it would be common sence to make this board with DDR3 as it is it's only fault as far as I can see.
We will probably see that board come out soon or next in line once they have sold enough of these to satify there egos.
Great board but,,,,just not yet I will be waiting for the next one out which will have to carry DDR3,,,if they want to go forward in thier technolagy.
hnolagy
VooDooAddict - Thursday, February 7, 2008 - link
For testers of large distributed systems this is an awesome thing to have sitting on your desk.You can have a small server room running on one of these.
The biggest shortfall I see is cramming enough RAM on it.
iSOBigD - Tuesday, February 5, 2008 - link
I'm actually very disappointed with 3D rendering speed. Going from 1 core to 4 cores takes my rendering performance up by close to 400% (16 seconds to 4.something seconds, etc.) in Max with any renderer. (I've tried Scanline, MentalRay and VRay) ...so I'm surprised that going from 4 to 8 gives you 40-60% more speed. That's pretty pathetic, so I suspect the board is to blame, not the software.martin4wn - Tuesday, February 5, 2008 - link
Actually 40-60% is not disappointing at all, it's quite impressive. You are encountering the realities of Amdahl's law, which is that only the parallel part of the app scales. Here's a simple workthrough:Say the application is 94% parallel code and 6% serial. As you add cores, say the parallel part scales perfectly, so doubles in speed with every doubling in core count. Now say the runtime on one core is 16 seconds (your example). Of that, 1 second is serial code and the other 15 seconds is parallel code running serially.
Now running on a 4 core machine, you still have the 1s serial, but the parallel part drops to 15/4 = 3.75 seconds. Total runtime 4.75s. Overall scaling is 3.4x. Now go to 8 cores. Total runtime = 1 + 15/8 = 2.87s. Scaling of 60% going from 4 cores to 8 cores, and overall scaling of 5.5x
So the numbers are actually consistent with what you are seeing. It's a great illustration of the power of Amdahls law - even an app that is 94% parallel still only gains 60% going from 4 to 8 cores even with perfect scaling, and it's really hard to get good scaling at even moderate core counts. Once you get to 16 or more cores, expect scaling to fall off even more dramatically.
ChronoReverse - Tuesday, February 5, 2008 - link
This is why I'm quite happy with my quad core. What would probably be the useful limit on the desktop would be a quad core with SMT. After that faster individual cores will be needed regardless of how parallel our code gets (face it, you're not getting 90% parallelizeable software most of the time and even then 8 cores over 4 isn't getting more than about 50% boost in the best case for 90% parallel code).FullHiSpeed - Tuesday, February 5, 2008 - link
Why the heck does this D5400XS MB support only the QX9775 CPU ??? If you need to use 8 cores you can get a lot more bang for the buck with quad core Xeon 5400 series, with only 80 watts TDP each, up to 3 ghz. For a TOTAL of $508 ($254 each quad ) you can have 8 cores @ 2 Ghz.Last month I built a system with a Supermicro X7DWA-N MB ($500) and 4 gig of DDR2 667 ($220) and a single 2.83 Ghz Xeon E5440 ($773) , which I use to test Gen 2 PCIE, dual channel 8 Gb/s Fibre Channel boards, two boards at once.
Starglider - Tuesday, February 5, 2008 - link
Damnit. AMD could've destroyed this if they'd gotten their act togther. Tyan makes a 4 socket Opteron board that fits into an E-ATX form factor;http://www.tyan.com/product_board_detail.aspx?pid=...">http://www.tyan.com/product_board_detail.aspx?pid=...
I was strongly tempted to get one before the whole Barcelona launch farce. If AMD hadn't made such horrible execution blunders and could have devoted the kind of resources Intel had to a project like this, we could have four Barcelonas running at 3 to 3.6 GHz with eight DDR2 slots all on a dedicated channel. Ah well. Guess I'll be waiting for Nehalem.
enigma1997 - Tuesday, February 5, 2008 - link
Note what Francois said in his Feb 04 reply re memory timing http://blogs.intel.com/technology/2008/01/skulltra...">http://blogs.intel.com/technology/2008/01/skulltra... Do you think it would help the latency and make it closer to DDR2/DDR3 ones? Thanks.enigma1997 - Tuesday, February 5, 2008 - link
CL3 FBDIMM from Kingston would be "insanely fast"?! Have a read of this artcile: http://www.tgdaily.com/content/view/34636/135/">http://www.tgdaily.com/content/view/34636/135/Visual - Tuesday, February 5, 2008 - link
I must say, I am very disappointed.Not from performance - everything is as expected on this front... I didn't even need to see benchmarks about it.
But prices and availability are hell. AMD giving up on QuadFX is hell. Intel not letting us use DDR2 is hell.
I was really hoping I could get a dual-socket board with a couple (or quad) PCI-express x16 slots and standard ram, coupled with a pair of relatively inexpensive quadcore CPUs. Why is that too much to ask?
The ASUS L1N64-SLI WS board has been available for an eon now, costs less than $300 and has quite a good feature set. Quadcore Opterons for the same socket are also available for more than a quarter, some models as cheap as $200-$250.
Unfortunately, for some god-damned reason neither ASUS not AMD are willing to make this board work with these CPUs. The board works just fine with dual-core Opterons, all the while using standard unbuffered unregistered DDR2 modules, but not with quad cores? WTF.
And that board is old like the world now. I am quite certain AMD could, if they wanted, have a refresh already - using the newest and coolest chipsets with PCIe 2.0, HT 3.0, independent power planes for each cpu, etc.
Intel could also certainly have a dual socket board that works with cheap DDR2, have plenty PCI-express slots, and the cheap $300 quad-core Xeons that are out already instead of the $1500 "extremes".
I feel like the industry is purposely slowing, throttling technological progress. It's like AMD and Intel just don't want to give us the maximum of their real capabilities, because that would devalue their existing products too quickly. They are just standing around idly most of the time, trying to sell out their old tech.
Same as nVidia not letting us have SLI on all boards, or ATI not allowing crossfire on nforce for that matter.
Same as a whole lot of other manufacturers too...
I feel like there is some huge anti-progress conspiracy going on.