PCB Design and Functionality

LGA1156 mainboards based on Intel P55 Express look a little unusual due to the fact that they use a single-chip core logic set without the North Bridge chip, which functions have been moved into the CPU. However, some of our upcoming reviews will also talk about more traditional design implementations, too. A lot of mainboards have the only chips of the Intel P55 Express core logic set – Platform Controller Hub – where the conventional North Bridge used to be. In this case it is usually equipped with too sophisticated cooling system involving heatpipes, just like before. The South Bridge spot is taken over by additional onboard controllers providing support for PATA and SATA storage devices and these chips are usually covered with a separate heatsink, just like the South Bridge chip. As a result, new mainboards look almost like the solutions based on previous chipsets, but I have to say that it is not true for Asus P7P55D Deluxe. You’d better get used to it, this is what a typical mainboard for Lynnfield processors should actually look like:

Since we came to speak about cooling solutions, let’s give due credit to Asus P7P55D Deluxe mainboard developers who have tackled this aspect extremely attentively. The only Intel P55 Express microchip is located where the chipset South Bridge used to be. It is cooled with a large but low-profile heatsink, which is more than enough even without any heatpipes. However, the heatsinks installed on top of the 16-phase processor voltage regulator circuitry use reliable screw-on retention not just for decorative purposes and are connected via a heatpipes for a reason. They bear the primary thermal load, besides the processor heatsink, of course, and this load increases substantially during overclocking.  Therefore, the heat generated by the processor voltage regulator circuitry at the bottom of the PCB is dissipated through thermal interface to a couple of additional metal backplates.

In order to provide a better-balanced, better-grounded and more objective estimate of the Asus P7P55D Deluxe mainboard efficiency, we have also tested the new processors on Gigabyte GA-P55-UD3 for the sake of comparison (the review of this mainboard will follow shortly). Although this is one of the junior mainboard models in the lineup, it is also equipped with a couple of pretty large heatsinks on the components of the CPU voltage regulator circuitry. However, they are fastened using common plastic push-pins and have no additional backplates at the bottom of the mainboard PCB. We noticed that its heatsinks heated up significantly during overclocking. Moreover, the PCB textolite under the heatsinks changed its color and became noticeably darker because of extreme overheating.

We didn’t detect any serious heatsink heating like that on Asus P7P55D Deluxe. It could be the case due to more phases in the processor voltage regulator circuitry, but it could also be due to more reliable screw-on retention and heat-dissipating backplates at the bottom of the PCB. All in all, we would like to give Asus developers a well deserved check-mark for very efficient and not too excessive cooling system they implemented on their P7P55D Deluxe.

As you may guess even from the model name, the functionality of Asus P7P55D Deluxe is more advanced than that of a mainstream mainboard on Intel P55 Express/ to begin with, contemporary LGA1156 mainboards are equipped with one PCI Express 2.0 x16 slot or two slots, which will switch to PCI Express 2.0 x8 mode when two graphics cards are used. They are supported by the PCI Express controller, which is now integrated into the CPU. There is also the third graphics card slot on Asus P7P55D Deluxe, but it uses the remaining four lanes of the PCI Express chipset and a graphics card installed into it will not work any faster than PCI Express 2.0 x4.

The developers had to use an additional JMicron JMB363 controller in order to implement support for PATA storage devices, because Intel chipsets haven’t featured their support for a long time already. Note that there is one “native” SATA port with a black connector and another SATA port split into two more with the help of JMicron JMB322 controller (dark-blue and gray connectors). The devices connected to these two ports do not require any drivers and can be easily tied up into RAID 0 or even 1 arrays without any special knowledge. In Asus terms, this technology is called Drive Xpert. As a result, Asus P7P55D Deluxe mainboard allows connecting up to nine SATA devices: six ports provided by Intel P55 Express and three more – by additional controllers.

Asus P7P55D Deluxe mainboard design looks good not only in general terms, but also has some very nice minor advantages. Power On and Reset buttons are lit up during work, and so is the small MemOK! Button that should help on first system boot-up if the computer cannot start because of incorrectly configured memory settings. There are special switches right above the memory DIMMs that allow sending slightly higher voltage to the CPU, the integrated memory controller and the DDR3 memory modules. There are green LEDs next to the switches, which will turn orange as soon as the voltage increases. The memory DIMM slots have thumb-locks only on one side, farthest from the graphics card, so the installed graphics card will not complicate taking out or putting in the memory modules. We really felt the difference from the wide grips on the graphics card slot lock. Scythe Zipang 2 processor cooler that we used during this test session is very wide and comes very close to the graphics card installed into the first slot. We would inevitably have problems with any other mainboard, but not with Asus P7P55D Deluxe: by gently pressing the tip of the screwdriver against the grip we could easily free the graphics card and take it out.

The connectors on the mainboard back panel are also quite diverse:

• PS/2 connectors for keyboard and mouse;
• Clear CMOS button;
• Optical and coaxial S/PDIF and six analogue audio-jacks implemented via ten-channel VIA VT2020 codec;
• Eight USB ports, six more ports can be connected to the onboard pin-connectors;
• IEEE1394 (FireWire) port implemented via VIA VT6308P controller, the second port is available as an onboard pin-connector;
• Two local network ports (network adapters built using Realtek RTL8112L and Realtek RTL8110SC Gigabit controllers).