P55 Chipset Overview



We have just one chipset now as typical Northbridge functions are moved onto the Lynnfield processor. Just like its Bloomfield-based Core i7 big brother, Lynnfield based CPUs have integrated memory controllers. The DDR3 memory channels are dual channel unlike the triple channel setup on Bloomfield. Lynnfield currently supports 16GB of memory, solidly placing it in the midrange category. However, official memory speeds now reach 1333MHz instead of 1066MHz on Bloomfield. The biggest difference between the two processer families is that Lynnfield stuffs 16 lanes of PCI Express 2.0 connectivity into the processor, thus alleviating the need for a Northbridge.

Those 16 PCIe 2.0 lanes can be configured as a single x16 link or split between a pair of x8s for multi-GPU configurations with a set of PCIe switches. CrossFireX support is a given but SLI support depends upon the motherboard manufacturer providing the right amount of funds to Nvidia for certification. For those unwilling to just accept 16 PCIe 2.0 lanes, EVGA already has a P55 board featuring the nForce 200 bridge chip with full support for three-way SLI.

What was known as the Integrated Controller Hub (ICH) on previous chipsets (such as the ICH10R) is now referred to as the P55 Express Platform Controller Hub, or PCH. The chip is based on 65-nm process technology. As such, it is a lot smaller than the ICH10 series with a total die area of around 76.5 mm².

  AMD SB750 Intel ICH10R Intel P55
Additional PCI Express None 6 x1 PCIe 1.1 8 x 1 PCIe 2.0
USB 12 ports 12 ports 14 ports
SATA (300MB/s) 6 ports 6 ports 6 ports
PATA 2 channels None None
RAID* RAID 0/1/5/10 RAID 0/1/5/10 RAID 0/1/5/10
HD Audio Interface Yes Yes Yes
Ethernet Not Integrated Intel Gigabit LAN Intel Gigabit LAN
Northbridge Interface 4 lane PCIe 1.1 DMI 1Gb/s each direction, full duplex DMI 1Gb/s each direction, full duplex

The P55 Express PCH provides six 3 Gb/s SATA ports, 14 USB 2.0 ports, a Gigabit Ethernet MAC , HD Audio interface, and eight lanes of PCI Express 2.0 goodness all for about $40. That price tag buys you two additional USB ports and two additional PCIe lanes over the $3 ICH10R. One other change worth mentioning is that the Gigbit Ethernet MAC will use one of those PCIe lanes if enabled.

The PCI Express lanes are version 2.0 but Intel decided to limit their speed to PCIe 1.x specs at 2.5GT/s. Why? We believe with the DMI link continuing to operate at 1GB/s in each direction, a decent 6Gb/s SAS/SATA RAID card and a few upcoming 6Gb/s drives could easily saturate the link. The P55 Express PCH consumes a little over 4.5W during normal operation. Considering the specifications on AMD’s upcoming SB8xxx chipsets, it appears we have a PCH Gap brewing.

Index Gigabyte GA-P55M-UD2 Features
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  • yacoub - Tuesday, October 06, 2009 - link

    785G is just onboard graphics halfbreed between 780 and 790 or whatever. until AMD releases a new line of high-end boards worth reviewing, why bother? Reply
  • haplo602 - Wednesday, October 07, 2009 - link

    P55 is just half a chipset, i5 took over some of the functionality anyway ... why bother ? Reply
  • tommy101 - Wednesday, September 08, 2010 - link

    beastyhacks79.smfnew.com the best psp hacking site Reply
  • bollux78 - Tuesday, October 06, 2009 - link

    Why do we need PCI anymore? I´ll tel you why: The PCI bus is more than enough for a hell bunch of applications, that´s it. If you have a damn good sound card or video capture, or whatever the card you have, and it´s PCI, you´d love to have the slot in there, because you don need to ditch that card and bet a "fantastic" PCIE x1 new card.
    C´mon people, let´s use the computer for the right purpose, not just to give money to the manufacturers buying new parts that you don´t
    necessarily need.

    I know, I´m being inflexible and oldschool, but, please, evolution is one thing, marketing is a completely different animal.
    Reply
  • strikeback03 - Tuesday, October 06, 2009 - link

    IMO it is more a board real estate problem than a case of buying the latest and greatest. On these P55 uATX boards you have 4 slots, one of which has to be devoted to graphics unless it is a headless server. If you use a dual slot graphics card (which a substantial portion of the readers on this site) you lose a second slot, and ideally you would have an open slot beneath that to ease airflow. So that leaves you with one or in a pinch two slots, therefore what interface they are is quite important. PCIe has been out on boards for what, 5-6 years now? I'd say its time to stop selling PCI cards and leave the PCI slots only on full ATX boards (plus maybe a few HTPC-oriented uATX boards) and let the interface finally die off.

    Though I'd say IDE has even less of a place now, SATA hard drives have been the norm for years and even optical drives for a few years. Time to upgrade if you are still carting one of those around.
    Reply
  • sonicdeth - Monday, October 05, 2009 - link

    Thanks Gary for the detailed review. Can't wait for the p55 roundup, and I'm also very interested now in your audo codec review. Reply
  • mindless1 - Monday, October 05, 2009 - link

    ... but I don't see the sense in SLI on mATX. Using the typical long video cards means you can't have a shorter depth case, just shorter height and since when is the area above your computer case a vital piece of real-estate?

    With 2, 8 or 16X slots onboard it only makes sense to me to go full ATX, is someone with the system budget to build a powerhouse gaming machine really poor enough, indescriminating enough, or young enough (to not have desirable cards from past systems) they don't want to add some other cards?

    I hate to say it but this is getting to be a madness, the idea that we need to focus centrally on gaming ability of a board. Most people are not hard core gamers, but factually speaking, most hard core gamers don't do SLI either. Granted you can use a 16x slot for cards with fewer lanes, that seems the only saving grace for the two boards.

    It's getting to the point I want a cTX case design where the drive racks are not in front of the mainboard and PSU, they are above them, so the case is even taller than std. ATX but not as deep.

    Might tip over a little easier but earthquakes are rare here and plenty of other household items are more tip-happy than that would be.
    Reply
  • strikeback03 - Monday, October 05, 2009 - link

    There are cases made to hold a uATX board lying on the bottom, making it kinda a wider Shuttle. I'm personally looking for full ATX as well though, as the height doesn't matter too much to me (pretty sure anything short of a ABS Canyon or some of the bizarre decorative cases would fit under my desk) and don't want to limit my slot selection. Reply
  • Sunburn74 - Monday, October 05, 2009 - link

    Hey Anand,
    Gigabyte boards have on issue that drives me nuts. As soon as you start overclocking them, you lose the ability to S3 sleep. When you do your maximal overclocks for various board reviews, would you mind testing if S3 sleep was maintained at those maximal overclocks?
    Reply
  • Gary Key - Monday, October 05, 2009 - link

    This board resumes from S3 (USB keyboard) at up to 215 Bclk (mentioned in the thoughts section, make that more visible next time) with our setup and that includes an external hard drive on the Firewire port which is properly instructed to shut down and restart. Reply

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