Electronic Design
 Tale of Two Motherboards

Tale of Two Motherboards

You may have noticed a short lull in Lab Bench Online. I have been waiting for our new website to be up and running. Now that it is we have lots of content including videos. I may try that for a future Lab Bench Online project but for now you can read about my latest exploits below.

Originally I was going to put together a single system based on Intel's Core i7 Extreme Edition based on the Nehalem architecture but Intel came through with the latest Core i5 processor. Likewise, Gigabyte was able to deliver its GA-P55A-UD6 motherboard for Core i5 and Core i7 processors. Not wanting to disappoint anyone I decided to build a pair of systems with the second based on Gigabyte's GA-X58A-UD7 that is capable of handling the Core i7 Extreme Edition.

You can check out the details of the various Best of 2009 components used in the projects using the related links so I won't go into all the options and features of each in this part of the article. Instead I will concentrate on contrasting the two systems especially since there are significant cooling differences between the motherboards.

For the Extreme Edition system I started with the  Gigabyte GA-X58A-UD7 motherboard, the Core i7 Extreme Edition processor, Corsair's Dominator DDR3 8 Gbyte memory kit, NVidia's GTX 260 video adapter and Seagate's new SATA III Barracuda XT. The GA-P55A-UD6 motherboard was paired with the first Lynnfield chip, the quad core Core i5 750. The video is provided by a Sapphire Technology AMD HD5770. The Best of 2009 choice was the faster HD5970 but getting one was tough due to high demand. They should be more readily available now and it was did roll around it would find a home plugged into the GA-X58A-UD7 motherboard. The HD5770 supports Microsoft’s DirectX 11 allowing games to take advantage of the advancements in the graphical hardware.

The motherboards and chips are similar but both have distinct differences. For example, the Core i7 has a 12 Mbyte cache and supports QuickPath, Intel's high performance chip interconnect. At 130W TDP, the Core i7 uses a bit more power than the 95W TDP Core i5 750. The Core i7 chip also support three memory channels versus the two for the Core i5. Another difference is that the Core i7 supports hyperthreading so its four cores appear as eight. Definitely handy for the virtual machine gyrations I planned to put the Core i7 through.

The motherboards reflect their processors. The GA-X58A-UD7 motherboard (Fig. 1) has a significantly heftier power and cooling infrastructure. It is also more ambitious when it come to PCI Express slots being able to handle up to three high performance video cards. The GA-P55A-UD6 motherboard (Fig. 2) is leaner but as structurally sound as its sibling supporting the same high speed USB 3.0 and SATA III interfaces that will become more common in the future. It can handle a pair of PCI Express video cards although its x16 PCI Express sockets are split between one supporting x16 and the other a x8 interface. As you might guess, the GA-X58A-UD7 is way ahead when fully packed but if a single video card is in the mix then the GA-P55A-UD6 holds its own. By the way, both cards can handle multiple ATI or Nvidia video cards working together via ATI Crossfire and Nvidia SLI support. The motherboards also us 2 ounce copper technology for a cooler, more durable circuit board. It also lower impedance. 

The back panel (Fig. 3) of the two motherboards is very similar so I show only one GA-X58A-UD7. Each has plenty of USB 2.0 ports, some paired with eSATA ports thereby providing power to external SATA devices. The motherboards also supply three times the power to USB devices. Likewise, the audio outputs includes Dolby Home Theater support. Outputs include coax and optical S/PDIF. Both types of IEEE 1394 interfaces are provided as well.

I mentioned the SATA III support but keep in mind that it is only on a pair of internal interfaces (Fig. 4). There are half a dozen SATA II ports. These are not slow but there is no need to put a SATA II drive on a SATA III port and it is a waste to put a SATA III drive on a SATA II port although it will work, just at the slower speed. The reason for the difference is cost and the fact that there are two different SATA controllers, one for SATA III and one for SATA II. This is reflected in the RAID support. The SATA III only supports RAID 0 and 1  since it only supports two drives. The other controller can also support RAID 10, 5 and 50.

For legacy support there is actually a floppy interface and an IDE interface (Fig. 5) but they are at the far end of the motherboard. Extra long cables may be required with some cases.

There are a host of other features like a very handy Dual BIOS, TPM (Trusted Platform Module) that allows secure access when a matched Bluetooth cell phone is in range, and a one click overclocking application, EasyTune 6, for those looking to peg the meter.

Now onto the production.


This will not be a blow by blow construction project. Putting together a system from scratch for most engineers and developers is something they can do in their sleep but there are some gotchas that always crop up. This was the case (pun intended) with this project.

Originally I was going to use old cases I have in the labs for both systems. This is one great thing about ATX motherboards. Unfortunately I ran into a problem when I chose the Evercool HPJ-12025 120mm Ever Lubricate Bearing Transformer 4 Heat Pipe CPU Cooler. It is rather tall. Likewise, the GA-X58A-UD7 motherboard comes with Gigabyte's Hybrid Silent-Pipe 2 heatpipe system (Fig. 6) that includes a heat sink that effectively takes up a slot so its fins can stick out the back of the case. It is almost as large as the Evercool HPJ-12025 heat sink (Fig. 7).

Well, the other motherboard wound up in an old ATX tower case but the GA-X58A-UD7 motherboard found a home in a new Cooler Master Storm Sniper mid tower ATX case (Fig. 8). It is a tight fit with both installed and it gets tighter when you add the memory cooling fans (Fig. 9). Given that the video cards also have their own cooling fans there is not much in the system that does not have a special cooling system. The exception is actually the hard drive.

The installation gets a bit tight with everything installed so make sure the cables (Fig. 10) are plugged in first. The other thing to keep in mind is the air flow direction of the case fans (Fig. 11) and the other fans within the system. They need to work together. The default case configuration actually works well with the side fan pulling air in and the others pushing it out. Only one of the Evercool fans fits given the close proximity of the memory fans. As noted, the direction of the airflow of the Evercool fan needs to match the fan on the back of the case. Also make sure you use ties on the cables so they do not fall into the fans. The fans are exposed so a loose wire can get tangled and stop a fan. Definitely not something you want with a hot machine like this.

Two reasons for choosing the Cooler Master Storm Sniper case were its internal width that allowed the Evercool heatsink to fit. The other was the plethora of large fans (4 with an option for a 5th). Cooling is critical if you plan on overclocking. Many go with liquid cooling but this approach was significantly cheaper and works very well.

I also happen to like the case's top panel with a fan speed adjust, four USB ports, an IEEE 1394 port, an eSATA port and audio jacks. It also looks slick with blue LED lighting on the fans. You can turn that off if you want.

I happened to use Corsair power supplies on both systems. The one thing to note with this system is the placement of the power supply. With this case, it is actually on the bottom and the cooling fan is aimed down. It is not even part of the motherboard and peripheral cooling system as with most system configurations. It is possible to flip the power supply but given the number and size of the fans already in the system this would only screw up the airflow while adding little to the volume of air being moved through the system. It also keeps the power supply cooler.

Some other things I really did not get to take advantage of on the case were the number of hard drive slots and the ease with which you can swap the drives. They are mounted sideways and internal, not hot swappable but very convenient.


Putting together the 1156 socket GA-P55A-UD6 was almost trivial. The stock CPU fan and heatsink were more than adequate given the lower TDP of the processor. Likewise the support chips run cooler. The motherboard still uses a heat pipe system but it does not need the extra slot of the cooling add-on. It still uses DDR 3 memory so the DIMMs still got a pair of cooling fans (Fig. 12) with a cool blue LED but that is all the light for this case. The LEDs are only visible when the case is open anyway.

The Sapphire Technology HD5770 (Fig. 13) still requires an external PCI Express power cable. If you move down a step in GPU performance you can get away without one. Move up to the HD5970 though and a pair of cables is in the works.

I did test the Seagate Barracuda XT with the motherboard and it does give a nice performance boost. Still, with only one drive the XT is living with the i7 and the i5 gets a regular 500 Gbyte Barracuda drive with SATA II support.


Normally I wouldn't go into the operating system configuration but I ran into a couple gotchas given my predilection for complex configurations. In particular, I wanted to play with a range of options from CUDA running on the Nvidia GTX 260 to multiple screens and multiple operating systems.

The Core i7 system now has 64-bit Centos 5 running on it but I had to go with KVM virtual machine support. I prefer Xen but you can't have Xen, CUDA and multiple monitors at this time. It works nicely with a single monitor.

I installed Centos first and found that my usual multiboot installations with Windows were another gotcha. Normally I install Windows first. In this case it was Windows Vista. I have not received Windows 7 so Vista is what gets put on PCs in the lab these days. The problem arises when you have another operating system installed on a hard drive and then try to install Vista. The Vista install does not like a hard drive with another boot partition. The trick is to setup up an NTFS partition on the drive and set it as the boot partition. Vista will happily install. This is easily done using an Ubuntu and gparted from a CD boot. The same is true using Centos although some may not prefer the command line recover mode. In any case, switching back to the Centos partition and Grub multiboot support allowed easy switching between operating systems.

You may ask why I did these multiboot gyrations given KVM support but keep in mind that giving a client operating system access to peripherals like the GPU is an interesting and more involved exercise. I do run Vista in a virtual machine for most of my software testing as long as the applications do not need access to the hardware. Unfortunately, running CUDA from Windows requires Vista running on the hardware, not in the virtual machine so dual boot occasionally gets a work out here.


I usually leave performance benchmarks to others but I will note that the Core i7 Extreme Edition definitely routes its i5 sibling as expected. For gaming and video editing, the Extreme Edition is definitely the way to go if you can.

On the other hand, the Core i5 is no slouch and runs rings around most of the other platforms in the labs, even a older dual Xeon system. From a gaming perspective, the GPU makes a major difference as well so matching the Core i5 with something like the HD5770 delivers impressive gaming performance.

One thing I will try in the future is to add a solid state disk drive to the mix. This should be able to take even greater advantage of the SATA III throughput. The Seagate Barracuda XT is the best at this point but physical limitations of disk technology hold back sustained transfer rates. Unfortunately, even the move to an SSD still leaves storage as one of the major bottlenecks because its write performance tends to be a limiting factor. Again, it is a matter of matching performance across the board. The Core i5 and i7 are fast but keeping up with the I/O can be a challenge depending upon the application. I will note that the Barracuda XT takes everything I through at it. I am using LVM (logical volume manager) creating dozens of logical partitions for virtual machines.

Bottom line, either of the systems will be a pleasure to use for most people exceeding their requirements. I know I am going to be taking good advantage of both of them. Of course, the Core i7 system (Fig. 14) still looks and runs the best.





Sapphire Technology


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